Preheat the oven to 200 F and line two baking sheets with parchment paper.
Thoroughly wash, dry, and core the apples, and slice them into ⅛-inch slices (use a mandolin if possible).
Arrange the apple slices in a single layer on both prepared baking sheets and sprinkle the cinnamon sugar over each slice.
Remove the trays and flip all the apples
Place back in the oven for 30 minutes
Remove one apple chip from the oven and let sit out for 3 minutes.
Now test to see if it has dried out enough and if not continue to test every 15 minutes.
The apples will still be a little pliable and harden as they sit out. If the apples get too crisp in the oven, they will become too brittle
Store in an airtight container.