Preheat oven to 200F degrees. Line two large baking sheets with silicone baking mats. Set aside.
Wash and thinly slice the apples. Spread the apple slices onto the baking pans making 1 single layer. Sprinkle with cinnamon and sugar.
Bake for 1 hour, flip the apples over, and bake for another 1-1.5 hours. Turn the oven off and keep the apples inside as the oven cools down for 1 hour. This will help them get crunchy. Some apples may just be chewy and only slightly crunchy after 3 hours in the oven. Store apple chips at room temperature in an airtight container for up to 1 week.