Preheat the Oven: Preheat your oven to 200°F (93°C). Line two to three large baking sheets with parchment paper or silicone baking mats.

Prepare the Apples: Wash and dry the apples thoroughly. Core and slice them thinly (about 1/16 to 1/8 inch thick). A mandoline slicer helps achieve uniform thickness for even crisping.

Prevent Browning (Optional): Toss the apple slices with 1 tablespoon of fresh lemon juice to prevent browning.

Season the Apples: In a small bowl, combine ground cinnamon and optional sugar. Sprinkle this mixture evenly over the apple slices and toss gently to coat evenly.

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

Bake Low and Slow: Place the baking sheets in the preheated oven. Bake for 1 hour. After the first hour, flip the slices over and bake for another 1-2 hours. Check for doneness after 2 hours. The chips should be dry, slightly curled at the edges, and no longer soft or pliable.

Cool for Crispness: Once done, leave the apple chips in the oven with the door slightly ajar for an additional 30 minutes to 1 hour to further crisp up, especially in humid environments. Alternatively, transfer them to a wire cooling rack to cool completely.

Store: Once fully cooled and crispy, store the chips in an airtight container at room temperature. They’ll last up to a week. For longer storage, freeze them in a freezer-safe bag, though they may lose some crispness when thawed.