Wash and dry the apples thoroughly. Using a sharp knife or mandoline, slice the apples into very thin rounds (about 1/8-inch thick). Remove any seeds.

In a small bowl, mix the cinnamon and sugar (if using). Lightly sprinkle the mixture over both sides of the apple slices.

Preheat the air fryer to 350°F (175°C) for about 3 minutes.

Arrange the apple slices in a single layer in the air fryer basket, ensuring they don’t overlap. You may need to cook in batches.

Air fry for 8-10 minutes, then flip the slices and cook for another 5-8 minutes until crispy and golden. Keep an eye on them to prevent burning.

Remove the apple chips from the air fryer and let them cool on a wire rack. They will crisp up further as they cool.

Store in an airtight container at room temperature for up to 3 days for best crispiness.