Vegetarian Hash Brown Breakfast Casserole
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This vegetarian hash brown breakfast casserole is packed with veggies, eggs and melty cheddar cheese, all baked over a crispy hash brown crust. It’s the perfect make-ahead breakfast or brunch dish for feeding a crowd.
If you’re looking for a hearty, crowd-pleasing breakfast, this vegetarian hash brown breakfast casserole is it. It starts with a crispy hash brown crust and is layered with sautéed veggies, fluffy eggs and plenty of melty cheddar cheese.
I love my sausage egg casserole, but I wanted to create a vegetarian egg casserole and if I do say so myself, this one hits the spot!
It’s one of my favorite recipes for brunch, meal prep or holiday mornings because you can make it ahead and it feeds a crowd with very little effort.
Table of Contents
- Why I Love This Vegetarian Breakfast Casserole
- Ingredients Needed
- How to Make this Hash Brown Breakfast Casserole
- Tips for the Best Breakfast Casserole
- What to Serve With Hash Brown Casserole
- How to Make Ahead, Store & Reheat
- Frequently Asked Questions
- Popular Breakfast Recipes
- Hash Brown Breakfast Casserole Recipe
“This casserole was a hit at a brunch party! I like that you crisp the hash browns first before adding the egg and veggies. Other recipes just toss the potatoes in with everything else and I definitely prefer the crispier potato layer in this dish.”
Why I Love This Vegetarian Breakfast Casserole
- That crispy hash brown crust: The hash browns bake first to create a golden, crispy base that makes this casserole extra special. It’s honestly my favorite part.
- Packed with veggies: Between the mushrooms, peppers, onions and spinach, every bite is loaded with flavor and a good dose of veggies.
- Perfect for feeding a crowd: This recipe fills a whole 9×13 dish, so it’s ideal for brunch gatherings, holidays or anytime you’re cooking for a group.
Ingredients Needed
- shredded hash browns – the base of this casserole! I actually prefer using frozen shredded hash browns here because they crisp up beautifully and make the crust super easy. No need to thaw before using.
- olive oil – helps the hash browns get golden and crispy and is also used to sauté the veggies. Avocado oil works great as well.
- veggies – a combo of onion, bell pepper, mushrooms and spinach adds tons of flavor and color. Feel free to switch things up with whatever veggies you have on hand.
- eggs – the eggs hold everything together and give the casserole that fluffy, custardy texture. I used 10 whole eggs, but you can swap in some egg whites if you prefer.
- milk – helps create a creamy egg mixture. Any milk works here, but I typically use unsweetened almond milk to keep things light.
- sharp cheddar cheese – adds that melty, cheesy goodness. I highly recommend shredding a block of cheese yourself for the best flavor and melt.
Find the full ingredient list with measurements in the recipe card below.
How to Make this Hash Brown Breakfast Casserole
Step 1: Preheat oven to 400°F. Add hash browns to a greased 9×13 baking dish, drizzle with oil, season with salt and pepper and bake for 30 minutes until starting to crisp.
Step 2: While hash browns bake, sauté onion, garlic, bell pepper and mushrooms in a skillet until softened. Stir in spinach and cook until wilted. Let cool slightly.
Step 3: In a large bowl, whisk together eggs and milk. Stir in the cooked veggies and 1 cup cheese.
Step 4: Pour egg mixture over the hash browns, top with remaining ½ cup cheese, and bake 20–25 minutes until the eggs are set. Let sit for 5 minutes before serving.
Tips for the Best Breakfast Casserole
- Cook off the mushroom moisture: Mushrooms release a lot of water as they cook. Let that liquid fully evaporate before adding the spinach so your casserole doesn’t end up watery.
- Shred your own cheese: I know it’s one extra step, but freshly shredded cheese melts so much better. Pre-shredded cheese has anti-caking agents that can make the casserole a little grainy.
- Let the casserole rest before slicing: Give it about 5 minutes after baking so the eggs can fully set. This makes it much easier to slice clean portions instead of a soft scoop.
What to Serve With Hash Brown Casserole
This hash brown breakfast casserole would be such a great brunch addition! Here are some foods that would pair well with this dish:
- With a sweet side: Fluffy cinnamon rolls, almond cake or easy berry cake – I love serving both sweet and savory options at brunch!
- Fresh fruit: Try my easy fruit salad, a kefir smoothie, or this green detox smoothie. You can’t have brunch without a little fruit, right?!
- Caffeine: Coffee (or tea) is a must for brunch. Try my whipped coffee, pumpkin spice latte, or a tasty iced matcha latte.
- Fun drinks: Mimosas or bellinis. If you’re looking to make this a fun brunch, these are my two go-to drinks!
How to Make Ahead, Store & Reheat
This casserole is perfect for making ahead, which makes it great for holidays, brunch gatherings or weekly meal prep.
- Make ahead: You can bake the casserole the day before, let it cool, then cover and store it in the fridge overnight. The next morning, let the dish sit at room temperature for about 10–15 minutes while the oven preheats to 350°F, then warm it in the oven for 20–25 minutes until heated through.
- Refrigerator: Store in an airtight container in the fridge for up to 5 days.
- Freezer: Once cooled, cut the casserole into individual portions and freeze in airtight containers for up to 3 months.
- Reheating: Individual slices reheat well in the microwave or toaster oven. For larger portions or the whole casserole, reheat in the oven at 350°F until warmed through. If frozen, thaw overnight in the fridge before reheating.
Frequently Asked Questions
The center should be fully set and no longer jiggly when you gently shake the dish. If you want to double check, insert a knife into the center. If it comes out clean, the eggs are cooked through. You can also use a thermometer — the center should reach about 160°F.
Nope! I actually add them straight from the freezer. They crisp up beautifully in the oven and make forming the crust super easy.
Yes, if you’re not keeping it vegetarian you can easily add cooked sausage, bacon or diced ham. Just stir it into the egg mixture before baking.
Popular Breakfast Recipes
If you enjoyed this recipe, please consider leaving a ⭐ star rating and let me know how it went in the 📝 comments below.
Hash Brown Breakfast Casserole
Ingredients
- 1 20 oz bag frozen shredded hash browns, about 4-5 cups
- 3 teaspoons olive or avocado oil, divided
- 1 cup yellow onion, chopped
- 2 cloves garlic, minced
- 1 red bell pepper, chopped
- 1 8 oz package mushrooms, chopped
- 1 5 oz bag of baby spinach
- 1 teaspoon salt, plus more to taste
- ½ teaspoon ground black pepper, plus more to taste
- 10 eggs
- ½ cup non-dairy milk, I used unsweetened almond milk
- 1 ½ cups shredded sharp cheddar cheese
Instructions
- Preheat oven to 400°F and spray a 9×13 baking dish with cooking spray.
- Add frozen shredded hash browns (no need to thaw) to baking dish and drizzle with 1 teaspoon oil and a dash of salt and pepper. Bake for about 30 minutes until potatoes start to brown and crisp up. Once you pull potatoes from the oven, press down with a spatula to help form the bottom crust more.1 20 oz bag frozen shredded hash browns, 3 teaspoons olive or avocado oil
- While potatoes are baking add 2 teaspoons oil to a large skillet over medium-high heat. Once hot, add onion, garlic, bell pepper and mushrooms. Cook until onions are translucent and all the liquid from the mushrooms has evaporated, about 7-10 minutes.1 cup yellow onion, 2 cloves garlic, 1 red bell pepper, 1 8 oz package mushrooms
- Add spinach, salt and pepper to the mixture and stir until spinach has wilted.1 5 oz bag of baby spinach, 1 teaspoon salt, ½ teaspoon ground black pepper
- Once veggies are cooked, take off heat and set aside to cool.
- Whisk eggs and milk in a large bowl.10 eggs, ½ cup non-dairy milk
- Once veggies have cooled and are no longer hot, add to egg mixture along with 1 cup shredded cheese and stir to combine.1 ½ cups shredded sharp cheddar cheese
- Pour egg mixture into the baking dish on top of the hash browns and top with additional 1/2 cup of cheddar cheese.
- Bake for 20-25 minutes until set and eggs are no longer jiggly.
- Let stand for 5 minutes and serve.
Notes
- Storage: Store leftover casserole in an airtight container in the refrigerator for up to 5 days. Individual slices can also be frozen for up to 3 months. Thaw overnight in the fridge before reheating.
- Make ahead: Bake the casserole the day before, let cool and store covered in the fridge. Reheat the next morning at 350°F for 20–25 minutes until warmed through.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Like This Recipe? Rate & Comment Below!
Baked to completion today, but not serving until 3 days from now. Should I keep in the fridge till then or freeze tonight? Thanks!
Yes, keeping it in the fridge will be totally fine. Just cover it well and reheat at 350°F until warmed through when you’re ready to serve. Hope you enjoy!
I’m getting ready to make this for the 4th time. Found this recipe when looking for a vegetarian recipe because my son’s girlfriend is vegetarian (but I am also gluten free). I made breakfast meat on the side and everyone loved it and was happy.
Yay! So glad this casserole has been a success for everyone, Patricia. Love that it’s become a repeat recipe for you. Thanks for making it and for coming back to leave a review. It means a lot!
Hi, Brittany! If I were to make this breakfast the day before and store it in the fridge, would the heating instructions be the same if I were to bake it the next day (400 degrees for 20-25 minutes)? I can’t wait to try this!
Yes! In the morning while you’re preheating your oven I’d remove the egg casserole from the fridge and let it come to room temperature for 10-15 minutes before putting in the oven. Let me know how it turns out for you!
So I completely botched the hash brown part and i had to remake that part using trader joes hash browns. I think its going to be great and hopefully the teachers love it! its for an elementary school welcome back breakfast.
Oh no! Sorry to hear that, but I’m glad you were able to save it with the TJ’s hash browns! I’m sure the teachers are going to love it. Thanks for making my recipe to share with the teachers for a welcome back breakfast. 🙂
Hello Brittany,
I made this recipe ahead of time to serve my bridesmaids breakfast. Could you please share the reheating directions for baking the entire casserole from frozen? I saw a little note about it, but could find the actual instructions. Thank you!
Hi, Grace. I’m so glad you made the recipe for such a special occasion — how fun! If you’re reheating the whole casserole from frozen, I recommend thawing it overnight in the fridge first. Once thawed, cover with foil and bake at 350°F for about 25–30 minutes, or until it’s heated through. If you’d like a crispier top, you can remove the foil for the last 5–10 minutes. Hope your bridesmaids loved it!
I bought frozen hash brown shreds for the first time and found your recipe to use them. I have made this casserole twice with different variations and pumped up garlic/added herbs. But it is really such a fantastic umami-rich casserole – my whole family raves.
Yay! That makes me so happy to hear. I’m so glad this recipe was a hit. Thanks for making it and for coming back to leave a review. I so appreciate it!
Loved! I did follow advice of another reviewer and seasoned the hash browns & cooked at 425 and stirred a few time to evenly cook. I used vegan products-Just Egg liquid, unsweetened coconut milk and violife shredded cheese and it turned out amazing!
(No mushrooms since I didn’t have any)
Yay! So glad you loved it, Cathy. Love hearing that the vegan swaps worked so well. Thanks so much for trying the recipe and for leaving a review. I really appreciate it!
Hi! I’m excited to make this recipe, but I’m a little confused about cooking the hashbrowns first and then adding the eggs on top and then cooking them again. The hashbrowns won’t burn from being in the oven that long? I’ve seen some other recipes that say to mix the hashbrowns in the egg mixture.
Hi Ashley – No, you shouldn’t have any issues with the hash browns burning. The egg mixture will help prevent them from getting too brown during the final bake. Let me know if you end up trying this recipe and how it turns out for you.
In my dad’s words, this was a solid B+. It was tasty and I’d make it again but with some improvements. First, my hashbrowns never crisped up. I’d put it on the bottom rack and maybe do those at 425 before lowering the temp and moving to the middle rack. Additionally, there’s not nearly enough seasoning in here. Just salt and pepper on the hashbrowns, no other steps?? I added some to the eggs and to the veggies and I’ll do even more next time. I’d also do more cheese, maybe 2-2.5 cups. It’s a large casserole after all. I also added an 11th egg as I needed some extra liquid to cover all the veggies. Overall though, great for Christmas morning.
Hi Kelsey – Thanks for the feedback! I appreciate it. Overall, I’m glad it was a hit for Christmas morning. Thanks for making it and for coming back to leave a review.
Do you think I could make this the day before?
Hi Samantha – Sorry if I’m not getting back to you in time, but it should be totally fine to make this the day before! You can easily reheat the entire pan or individual slices when you’re ready to serve. Definitely come back and let me know if you tried it and what you think of it.
I doubled this recipe exactly for a Pajama Birthday Brunch. It was perfect for the occasion and everyone raved about it. Thank you for help in making my party a success!
Yay! So glad this recipe was a hit. Thanks for making it and for coming back to leave a review. I so appreciate it.
I made this casserole to have for breakfast for the week. It is so tasty and SO SATISFYING for not a lot of calories. It’s easy to swap out/add whatever you want – I left out the red peppers and added some chopped up chicken sausage. Next time I’ll put the spinach in with the mushrooms and onions and little earlier so it will wilt a little more.
Yay! So glad you loved this recipe, Jodie. Thanks for making it and for coming back to leave a review. I so appreciate it!
Yay! So glad you loved this recipe, Jodie. Thanks so much for making it and for coming back to leave a review. I really appreciate it.
I made this today. I had broccoli I needed to use; so I added that, plus spinach, chopped ham, and the other ingredients …..complete meal!! I served with fruit salad and toast. I did not add milk to the eggs and used 11 instead of 10. Anytime I have ever put milk in an egg casserole it turned out too liquidy (if that’s a word). That’s probably just me. : ) This turned out perfectly and was delicious!! Thanks, I will make again!!
Hi Kathy! I am so glad you gave this recipe a try and it turned out amazing for you. Thank you for taking the time to share your review & star rating, I really appreciate it!
This looks great, have never made an egg casserole before! Silly question. Can I use half and half instead of almond milk ?
Hi Ellen – I hope you love this recipe, it is so delicious. If you want to swap the milk, I would recommend using regular milk over half and half. Hope that helps and you enjoy this casserole!
thank you for the recipe!
we’re dairy free so I added a little shredded daiya to my side and my husband went without. we both really enjoyed it.
Sounds amazing, Samantha. I am glad you loved this recipe and it turns out great for you. Thanks so much for sharing your review + star rating, I truly appreciate it!
I followed the recipe except I omitted the mushrooms. It was wonderful, and I will definitely make it again.
YUM! I am so glad you loved this recipe and it turned out amazing for you, Jacki. Thank you for sharing your review + star rating, I truly appreciate it!
Leslie again. Just saw your note about making ahead of time. sorry for the repeat question.
Just wonder if it will be as good that way.
Hi Brittany,
Is this recipe that can be made the night before???
Hi Leslie! Yes, this will be as delicious if made the night before, but I do recommend reheating in the oven for best results! Enjoy!
Made this for breakfast and it was delicious. Didn’t have mushrooms so I substituted a crookneck squash. Easy recipe to work through – the first 30 minutes only the hash browns cook is plenty of time to prep and chop the rest of the dish. Will be making this again and again! Thank you!
AMAZING! I am excited to hear that you are loving this casserole and it is a hit for you, Lori. Thanks so much for coming back to share your review & star rating, I really appreciate it!
Hi!! Can this be made ahead of time?
Sure! Instructions on how to do this are listed above in the “how to make ahead” section. But basically you’ll want to bake completely the day before and cool completely before putting in the fridge. Then you can reheat when you are ready to serve. Hope that helps!
I’m wondering if this could be made vegan with Just Egg?
I haven’t tried it, but I just googled and it does look like people are using Just Egg to make casseroles like this so I don’t see why not! If you give a try, will you please report back?
Would this work with a crust or perhaps crustless version, or would I have to adjust the recipe/cooking time?
Hi Gretchen – Are you looking to add a crust to this? It is already crustless.
I added plant-based breakfast sausage crumbles and it was amazing! Great Christmas brunch egg dish!
YUM! I am so glad you gave this recipe a try and it turned out great for you, Brianna. Thank you for sharing your review & star rating, I really appreciate it!
I love this recipe and have made it so many times! It is so versatile as you can switch up the veggies and the cheese. I’ve used shredded cheddar, cottage cheese, vegan cheese and all were wonderful. I’ve also used regular hash browns, sweet potato hashbrowns and root vegetable hashbrowns. I always serve it with sliced avocado and another favorite topping is Peruvian green sauce. Thanks for sharing this gem!
WOO! I am so glad you found this recipe and it turned out great for you, Deanna. I love hearing the different variations you have use for this recipe, sounds so delicious. Thank you for your review & star rating, I really appreciate it!
This casserole was a hit at a brunch party! I like that you crisp the hash browns first before adding the egg and veggies. Other recipes just toss the potatoes in with everything else and I definitely prefer the crispier potato layer in this dish.
YUM! I am so glad this recipe is a hit, Lauren. Thank you so much for sharing your review + star rating, it means so much to me!
Hi Brittany, thanks for this recipe! I made it over the weekend and am enjoying it over this week for breakfast. A question: though I made it with frozen hash browns, do you have any suggestions on what I can use in place of that?
Hi Raymond! I am so glad you’re enjoying this recipe. Are you looking to replace the hash browns all together or just not have them be frozen?
Hi Brittany, I was looking to replace them all together. I do actually enjoy the potatoes (they also add some good “bulk”) but was wondering if you had any ideas to mix things up. thank you!
Hi – I don’t think I would recommend replacing the hash browns in this recipe, they help everything come all together. But you could mix up the veggies if you wanted to mix things up a bit. I also have my Sausage Egg Casserole with Veggies or my Healthy Breakfast Casserole that you might enjoy.
My family and I absolutely love this recipe.
Yay! I am excited to hear that you and your family are loving this recipe, Kristine. Thank you for coming back and sharing your review & star rating, I really appreciate it!
I made this casserole for New Year’s Day brunch and it came out perfectly. I like how it included everything I love about breakfast in one dish. I also added a little bit of sausage to it for my non-vegetarian-minded family. Thanks for the recipe!
Hi Caitlyn – So glad this casserole was a hit! Thanks for making it and for coming back to leave a review. I so appreciate it!
Great recipe! Amazing flavors! I prepped and sautéed the veggie mix a couple days ahead of time to save time on Christmas morning.
Everyone loved it! Made one with cheddar and one with feta. I think I may skip the hash browns next time. I didn’t feel it added much to the dish and would be one less step.
Love getting your emails, thanks Brittany!
WOO! I am so glad this recipe is a hit, Emily! Thank you so much for sharing your review + star rating, I really appreciate it!
I made this this morning! I added turkey bacon! My family loved it! Thank you for this great recipe! Merry Christmas.
YUM! Turkey bacon is such a great addition, Kristine. Thank you so much for sharing your review & star rating, I really appreciate it.
To pre-make, do I bake it and then reheat the next morning, or omit baking until the next morning? Can’t wait to try.
Hi Kara – I would recommend baking it the night before and reheating it the next morning. Hope you love this recipe!
Do you defrost the hash brown potatoes before baking?
Nope, no need to defrost the hash browns before baking!
Could you make it without the eggs? Would you need to add something else to the veggies?
Hey Sheri – The eggs are a big component of this recipe so unfortunately, I’m not sure how it could be made without the eggs.