Preheat oven to 300 degrees F (150 degrees C). Line 2 baking sheets with parchment paper.
Combine Parmesan cheese and thyme leaves in a bowl. Drop heaping teaspoonfuls of the mixture onto the lined baking sheets, spacing them 2 inches apart. Lightly press with your fingers to flatten them into circles 2 inches in diameter.
Bake in the preheated oven until slightly browned and crisp, 8 to 10 minutes. Cool slightly on the baking sheets, about 2 minutes. Loosen edges with a spatula and lift off the parchment paper. Transfer to wire racks and let cool completely until firm, about 10 minutes.