Lightly coat a large baking sheet with cooking spray; set aside. Using a 2-1/2- to 3-inch heart-shaped cutter, cut heart shapes from cheese slices. Set cutouts aside. (Tear scraps and save for another use.)
Unroll pizza dough onto the prepared baking sheet. Roll to a 16x12-inch rectangle. Spread pizza sauce over pizza dough. Arrange pepperoni over sauce. Sprinkle with Parmesan.
Bake in a 400 degree F oven for 10 minutes. Add cheese cutouts and bake 2 to 3 minutes more or until cheese melts and crust is golden. Cool on a wire rack 5 minutes. Cut into 12 squares. Makes 6 servings (2 each).