Slice apples to 1/16” using a mandolin slicer. I like to slice them horizontally so that there are star designs from the seeds.
Mix powdered sugar and cinnamon together.
Place apples single layer on parchment paper on cookie sheets and sift cinnamon mixture over the top. Flip and do the same on the other side.
Make sure that none of the apples are overlapping. Put in oven.
Cool for 2 hours, flipping the apples after 1 hr.
Take out a few apples and allow to cool for 5 minutes. If crispy once cooled, they are done. If they are still soft, continue to bake them in 15 minutes intervals.