Preheat oven to 350 degrees.
Grind old fashioned oats in a food processor until you get a "flour" texture.
Mix dry ingredients - oat flour, cocoa powder, coconut flakes, baking powder, and salt.
Mix wet ingredients in a stand mixer - mashed banana, egg, maple syrup, almond milk, and vanilla extract.
Add dry ingredients to wet ingredients; mix until combined.
Slowly add batter to a mini donut pan. I poured my batter into a Ziploc bag and cut one corner, to make this easier.
Bake for 12-13 minutes.
Optional topping: Whisk together vanilla yogurt and unsweetened cocoa powder. Spread onto each donut and top with sprinkles. If you add the yogurt "frosting", keep the leftover donuts refrigerated.