Lay out the buttermilk biscuits.
Spray the air fryer basket with non-stick cooking spray, so they don't stick.
In one bowl, put the melted butter and in the other bowl, put the sugar and cinnamon. Dip the raw dough first into the butter and then into the cinnamon/sugar mixture.
Place the biscuits into the air fryer basket.
Air Fry for 7 minutes at 350 degrees F.
As the donuts come out of the air fryer, roll them again in the butter, then the cinnamon sugar mixture.
Plate, serve and enjoy!