Preheat air fryer to 350F.
In a large bowl, add the self-rising flour, sugar, greek yogurt, mashed banana, and vanilla extract. Mix until well combined.
Lay the dough on a generously floured surface. Sprinkle some more flour on top of the dough. Use your hands to knead a couple of times, until the dough becomes smooth.
Roll the dough out into a rectangle about ½" thick, the dimensions don't have to be perfect.
Divide and cut the dough into 16 pieces.
Place a piece of parchment paper in the basket of your air fryer. Working in batches, transfer the dough pieces to the air fryer.
Brush the tops with melted butter.
Air fry at 350F for 4 minutes, gently flip and air fry for another 3-4 minutes, or until golden brown.
While baking, mix the sugar and cinnamon together in a small bowl, for the coating.
Remove donuts from the air fryer and immediately toss in the cinnamon sugar.
Serve warm with melted chocolate of choice.
