1. Preheat oven to 250 degrees.
2. Cut apple in half, remove seeds and slice each half as thinly as possible.
3. Sprinkle liberally with cinnamon.
4. Bake for 30-45 minutes. Remove from oven and flip over the apple slices. Sprinkle with cinnamon again (canâ€™t have too much of a good thing in this case) and bake for another 30-45 minutes.