To begin, preheat your oven to 350 and spray two donut pans with non-stick spray.
In a small mixing bowl, add your oat flour, cocoa powder, baking soda and salt and whisk them together thoroughly till there are no cocoa powder clumps.
In a large mixing bowl, add your coconut oil, maple syrup, Greek yogurt and milk and whisk together till well combined (with no yogurt clumps). Add your vanilla and egg and whisk together again.
Pour your dry ingredients into your wet ingredients and stir them together till well combined, forming your donut batter. Let your batter rest for 5 minutes, for the oat flour to soak up some of the wet ingredients.
Now, you can take spoonfuls of batter and fill the donut cavities, filling each one about 3/4 way full. Or, you can pipe your donut batter into the pan, using a piping or ziploc bag.
Bake in the oven for 8-10 minutes, or till the donuts are springy to touch.
To a small mixing bowl, add your powdered sugar and cocoa powder and whisk them together thoroughly, so there are no cocoa powder clumps.
Add your milk and vanilla, and whisk again till you have a smooth, even glaze.
After your donuts have cooled, you can carefully dip the tops of your donuts in your glaze, or you can drizzle the glaze across the tops of them with a spoon.
Add sprinkles, and devour!
I recommend storing these in an airtight container in the fridge, and they will last about a week stored that way.