To begin, preheat your oven to 350 and spray nonstick spray in a muffin pan.
In a small mixing bowl, add your dry ingredients and stir them together (oat flour, baking powder, baking soda, salt, cinnamon and nutmeg).
In a large mixing bowl, add your wet ingredients and whisk them together (mashed banana, sugar, coconut oil, almond milk, vanilla and eggs).
Add your dry ingredients to your wet ingredients and stir them together till all is well incorporated. Lastly, fold in your chopped walnuts.
Fill each muffin cavity about 3/4 way full, until all of your batter has been used up.
Bake in the oven for 16-18 minutes, or till the tops of the muffins are springy to touch and a toothpick inserted comes out clean.
Let cool, and devour!
Stored on the counter, in an airtight container, these muffins will only last about 2-3 days. Stored in the fridge, these muffins should last about a week. You can also freeze them for later.