Easy Cheesy Spaghetti Bake

1/2 pound ground beef
1 3/4 cup spaghetti sauce (14 ounces)
2 cups shredded mozzarella cheese
8 ounces spaghetti, cooked and drained

Brown beef; stir in sauce and cook on low heat for 5 minutes. Then toss with 1 cup of mozzarella cheese and all of the spaghetti. Spray an 8 inch square baking dish with cooking spray. Spoon mixture into dish, top with remaining cheese. Bake at 375 degrees for 15-20 minutes until cheese is melted.