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
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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!