In a mixing bowl, combine the granulated sugar and ground cinnamon. Mix well until evenly distributed. Set aside.
Preheat your air fryer to 350°F (175°C).
Open the can of refrigerated jumbo biscuits and cut each biscuit into quarters.
Roll each quartered biscuit piece into a ball between your palms.
Brush each donut hole with melted butter using a pastry brush.
Arrange the donut holes in a single layer in the air fryer basket. Cook for about 5-7 minutes, or until golden brown.
Remove the donut holes from the air fryer and toss them in the cinnamon sugar mixture until fully coated.
Let the donut holes cool for a minute on a wire rack before serving.
