1. Cook manicotti as directed. Drain and rinse with cold water. While manicotti is cooking, brown the ground beef. Drain and set aside to cool.
2. Preheat oven to 350 degrees F. Spray 9x13 inch baking dish with cooking spray. Mix 3 cups of the mozzarella with the ground beef and cream cheese. (I do this with my hands, it mixes better) Stuff the manicotti with the cheese mixture and place in the prepared dish. Spoon the tomato sauce over the manicotti. Sprinkle the manicotti with the remaining mozzarella.
3. Bake for 15 minutes. Sprinkle with the parmesan cheese. Bake for 10 minutes longer.