Preheat oven to 350°F.
Prepare a muffin pan by spraying it with cooking spray or lining it with silicone liners.
Make your flax egg by whisking together ground flaxseed with water in a small bowl with a fork and let it sit for a few minutes until it forms a gel-like consistency.
In a large bowl, combine the dry ingredients (flour, baking powder, baking soda, cinnamon, pumpkin pie spice and salt).
In a medium bowl, mix together the wet ingredients and sugar (pumpkin, coconut sugar, maple syrup, vanilla, oil, applesauce and flax egg).
Add the wet mixture to the dry ingredients and stir until just combined. Gently fold in any mix-ins if using.
Place batter into the muffin pan by the spoonful filling each cavity about ¾ full. The batter should be enough to make 10 muffins. Place on the center rack of your oven.
Bake for 18-20 minutes or until a toothpick inserted in the middle comes out clean.
Allow muffins to cool before removing from pan and serving.
Store muffins in a container at room temperature for 2-3 days, in the refrigerator for up to one week or in the freezer for up to 3 months.