Preheat oven to 400 degrees F.

Spray 6 cups of a muffin tin with cooking spray. Set aside.

Roll out dough on a floured surface. Using a small bowl that is about 5-inches in diameter, cut 6 rounds from the dough. Line each prepared muffin cup with one dough round, forming a cup.

In a medium bowl, stir together pepperoni, marinara sauce, and ½ cup of mozzarella. Spoon mixture evenly into each of the dough cups. Top with remaining mozzarella cheese and sprinkle with Parmesan cheese, if desired.

Bake for about 10-15 minutes, or until dough is cooked through and golden brown and cheese is melted.