Heat the oven to 400°F. Lightly spray 9 muffin tin cups with non-stick cooking spray.

Unfold pastry sheet. Cut into 9 squares. Place each dough square into prepared muffin tin. Top each with 1 teaspoon pizza sauce. Sprinkle each with 1 teaspoon mozzarella cheese. Top each with 4 to 5 slices pepperoni. Top with a small amount of remaining cheese.

Bake 20 to 22 minutes, or until golden browned. Let cool in pan 5 minutes before removing.