Preheat the oven to 350 degrees. Grease a donut pan. (Even if it is non-stick, I still recommend greasing it).
In a medium sized bowl, whisk together the gluten free flour, sugar, unsweetened cocoa powder, baking soda, and salt.
Add the melted vegan buttery spread, mashed banana, vinegar, vanilla, and non-dairy milk. Stir well.
Spoon the batter into the prepared donut pan.
Bake at 350 degrees F for 11-14 minutes.
Let the donuts cool in the pan for about 10 minutes, then turn the pan over onto a cookie sheet and tap to remove the donuts. While the donuts cool, you can make the frosting.
Make the frosting:
Beat the vegan buttery spread until fluffy. Add the confectioner's sugar and cocoa powder, then drizzle in a little of the non-dairy milk. Beat until smooth and creamy, adding more milk as needed.
Frost the cooled donuts with an offset spatula. Enjoy!
Notes
Store leftover donuts in an airtight container. They should be good for 2-3 days, but they really are best when fresh.Nutrition facts are for one donut.