Wash 2 apples and dry them well.
Line the air fryer basket with parchment paper.
Working with one apple at a time, slice a little piece off the stem end and the blossom end so both ends of the apple are flat.
Use a mandoline slicer to slice the apple into thin slices, and remove any seeds left on the slices. We leave the skin as it is very nutritious. We also leave the core to show the star in the middle of the slices. Always use the guard when using a mandoline slicer to protect yourself.
Place apple slices on a paper towel lined baking sheet in a single layer and pat dry. Work with one apple at a time.
Mix 2 teaspoons white sugar with ½ teaspoon cinnamon in a small bowl.
Using half the cinnamon sugar mixture, sprinkle it equally on apple slices lightly on one side. Use your finger to spread the cinnamon sugar around each apple slice to distribute it evenly. Try to be as even as possible as the sugar helps to crisp the apple chips. Reserve the other half of the cinnamon sugar mixture for the 2nd apple.
Place prepared apple slices into the parchment lined air fryer basket in a single layer with the cinnamon sugar side up. Be sure to place the apples in a single layer, and reserve the remaining apple slices to air fry in subsequent batches. One apple will be at least 2 batches.
IMPORTANT: Place your metal air fryer rack, rack side down, flat on top of the apple slices to hold the apple slices down while air frying. The apple slices will not be heavy enough to hold down the parchment paper. The rack is a must to keep the parchment paper from flying up into the air fryer burner for proper air fryer safety. Air fry at 350°F for 4 minutes, then turn each apple chip over and rearrange into a single layer again.
Air fry another 4 minutes and turn each apple chip over and rearrange into a single layer again.
Air fry another 2-4 minutes until apple chips are crisp to your liking. The edges will curl up during air frying.
Remove from air fryer and cool completely on a wire rack. Apple chips will crisp when cooled.
Repeat the steps above with the 2nd apple.