Combine sugar, brown sugar, salt and cinnamon in a small bowl and whisk to combine the set aside.
Lay your biscuits out on a flat surface, then use a clean bottle cap or similar size cookie/biscuit cutter to press into the center of the biscuit creating the hole of the donut. Repeat this until all the holes are creating, do not discard the dough you can use it to make donut holes.
Mist the basket of your air fryer* with olive oil or use a paper towel to wipe the surface down. Place four donuts (or as many as you can fit without any touching) in the basket of the air fryer then close the lid.
Press START then AIR CRISP, set the TEMP to 360 degrees F and set the TIME for 10 minutes then press the START button again. Check a couple times to make sure they do not over bake.
After 10 minutes open the air fryer and remove your finished donuts. They should be golden brown and crisp on the outside. Repeat this process until all the donuts and holes are air fried. I find that the second batch of donuts needs 7-8 minutes of bake time and the holes need 2-3 minutes.
Once all the donuts are air fryer, dredge the donuts one at a time in the melted butter letting the excess drip off. Then place the donut into the bowl of cinnamon sugar mix and coat on all sides. Repeat until all donuts are coated.
Enjoy warm immediately, or store leftovers appropriately. Enjoy!
Leftover Storage: Store leftover donuts in an airtight container at room temperature for up to 4 days. Rewarm, or enjoy cold. *Air Fryer Note: I use my Ninja Foodi 6.5 quart air fryer for these donuts. I can fit 4 comfortably and the bake time is consistently 10 minutes for the first batch. Depending on the size of your air fryer you may have to do more or less batches and the bake time may vary. Please open the air fryer and check the donuts every few minutes to ensure they do not burn.Biscuit Note:I recommend using Pillsbury Grands Flakey Layers Canned Biscuits if you can find them at your local grocery store. Any Grands will work, and I used Southern Homestyle and the donuts turned out well still. If using regular sized canned biscuits the cook time will need to be cut in half.