Preheat oven to 400F and move the rack to the middle position. Line a large baking sheet with parchment paper or a Silpat silicone baking mat.
Grate the Parmesan cheese finely.
Make tablespoon-size piles of the grated cheese on the parchment paper, spacing them an inch or so apart. I made mine a bit larger than tablespoon-size, but anywhere around there will work.
Bake the cheese for 5-7 minutes or until it's nicely bubbly and the edges are golden. The first batch will take a bit longer since the baking sheet is going in cold. You don't want them to be too brown or the cheese will taste bitter.
Let the cheese crisps cool for a few minutes on the baking sheet. You can eat them immediately or store them in a sealed container for a few days.