Cut your cheese slices into circles or squares, about 1" across.
Spread out cheese onto a parchment-lined cookie sheet and let sit on the counter for 2-3 days until it dries out completely. (You want them to make a little tap sound when you tap them on the counter.)
If they sweat out some moisture, periodically dab them dry with a paper towel.
Once your cheese is hard and dry, bake them in a 400-degree oven for 5 minutes.