For the filling: In a bowl combine the mozzarella cheese, pepperoni, and pizza sauce. Set Aside. Separate the biscuits. Flatten the biscuits to 3 inch circles. Place about 1 rounded tablespoon filling in the center of each circle. Bring the edges of dough together. Pinch to seal. Place, seam side down, on a greased baking sheet. Brush with milk. Sprinkle with Parmesan. Bake in a 350ºF. oven for 12 to 15 minutes or until golden. Serve warm. Makes 20