Take each apple and carefully cut the core out of the center so there is a big cylindrical hole running from north to south on the apple. Carefully slide each apple through a mandoline slicer to produce slices that are about 1/8 inch thick.
Lay out the slices on parchment paper on a cookie sheet. Bake at 200 degrees for approximately 1 hour, or until apple slices are slightly browned and crispy.
Dust with cinnamon if desired. Serve anytime; keep them stored in an airtight container.