Make the glaze by combining confectioner’s sugar with milk in a small bowl. Make the cinnamon sugar by combining the granulated sugar with the cinnamon in a separate bowl.
Remove the biscuits from the roll and place them in a baking sheet.
Using a small 1-inch round cookie cutter, cut a hole in the middle of each biscuit.
Using a brush, cover the inside of the air fryer with vegetable oil.
Place 3 or 4 donuts in the bowl of the air fryer making sure they don’t touch each other.
Air fry them at 350 F for 6 minutes, flipping them over after 3 minutes.
Place half of the donuts upside down into a shallow dish containing the glaze, and brush the other half with melted butter and invert them into the cinnamon sugar.