Preheat your oven to 200°F (95°C). Line two baking sheets with parchment paper or silicone baking mats.

Wash and core the apples. Using a sharp knife or a mandoline slicer, slice the apples very thinly—about 1/8 inch thick or thinner for crispier chips.

To keep apple slices from browning, you can toss them gently in a bowl with a little lemon juice diluted in water (about 1 tablespoon lemon juice per cup of water), then drain.

Lay the apple slices in a single layer on the prepared baking sheets. Make sure they don’t overlap.

If desired, mix cinnamon and sugar together and lightly sprinkle over the apple slices for extra flavor.

Bake in the preheated oven for about 1.5 to 2 hours, flipping the slices halfway through baking. Keep an eye on them to avoid burning. The chips are done when they are dry and crisp.

Remove from oven and let the apple chips cool completely on a wire rack—they will crisp up more as they cool. Store in an airtight container at room temperature for up to a week.