Preheat oven to 350°F (175°C).
Cook manicotti shells in boiling water until al dente. Drain and rinse with cold water.
In a bowl, combine ricotta cheese, 1 cup mozzarella, Parmesan, egg, parsley, salt, and pepper.
Stuff cooked shells with the cheese mixture and arrange in a greased 9x13 inch baking dish.
Pour pasta sauce evenly over the stuffed shells.
Sprinkle remaining mozzarella cheese on top.
Cover with foil and bake for 30 minutes. Uncover and bake an additional 10 minutes, until bubbly.