Preheat oven to 220 degrees and line two baking sheets with parchment paper.
Use a mandoline slicer or a sharp knife to cut the apples into thin slices, discarding the seeds. Place apple slices onto prepared baking sheets.
In a small bowl, mix together the ground cinnamon and ground cardamom.
Sprinkle the apple slices with HALF of the spice mixture.
Bake at 220 degrees for 1 hour and 30 minutes.
Remove from the oven, flip the apple slices over, and sprinkle with the rest of the spice mixture.
Return the pans to the oven rotating the pans from the top rack to the bottom racks.
Bake again for another 1 hour and 30 minutes.
To test for doneness: remove a couple of baked apple chips from the oven and let them cool on a plate for a couple of minutes to see if they get crispy. If they are crispy to your liking, they are done. If not, continue baking for a few minutes longer until the apple chips feel dry to the touch and crisp up within a couple of minutes of cooling.
Be sure to store the apple chips in an airtight container and they will stay crisp for up to a week.
Recipe adapted from The Gunny Sack