PREHEAT oven to 350° F.
COMBINE 3/4 cup mozzarella cheese, ricotta cheese, Parmesan cheese, egg and pepper in medium bowl. Stuff each shell evenly with cheese mixture; place in ungreased 12 x 7 1/2-inch baking dish. Pour sauce over shells.
BAKE for 25 minutes or until bubbly. Top with remaining 1/4 cup mozzarella cheese. Bake for an additional 5 minutes or until cheese is melted.