Peel, core, and slice apples into thin slices or rounds, about 1/8 inch thick.
Optional: Sprinkle with ground cinnamon for a warm, cozy flavor.
Arrange slices on dehydrator trays in a single layer with space between each piece.
Set the dehydrator to 135°F and dry for 8–10 hours until slices are dried.
Cool completely, then store in airtight jars in a cool, dark place.