Prep the apples: Wash and dry the apples well. You can leave the peel on for color and fiber. Core them if you prefer, or keep the cores and remove seeds only for a pretty “flower” center.

Slice thinly and evenly: Use a sharp knife or mandoline to slice the apples into 1/16–1/8 inch rounds. Thinner slices get crispier; thicker slices will be chewier.

Pat dry: Lay slices on a clean towel and pat to remove excess moisture. This small step helps them crisp instead of steam.

Season: In a small bowl, mix cinnamon with sugar (if using) and a pinch of salt. Place apple slices in a bowl, lightly spritz with oil if desired, and sprinkle the cinnamon mixture. Toss gently to coat.

Preheat the air fryer: Set to 300°F (150°C) for 3 minutes. A warm basket helps prevent sticking and promotes even cooking.

Arrange in a single layer: Place slices in the basket without overlapping. Work in batches as needed for best results.

Air fry and watch closely: Cook at 300°F (150°C) for 14–18 minutes, flipping once halfway. Start checking at the 12-minute mark. Edges should look dry and curled, with a light golden color.

Let them crisp: When they look almost done, remove and let the chips cool on a wire rack for 5–10 minutes. They will firm up as they cool.

Repeat with remaining slices: Keep finished chips in a bowl or container uncovered until fully cooled, then store.