- Preheat oven to 400 degrees.
- Half or quarter meatballs and place in a large bowl. Reserve 2 1/2 cups spaghetti sauce. Pour the remaining sauce over the meatballs and stir in 1/2 cup water.
- In a separate bowl, combine the egg, ricotta cheese, and 1 cup mozzarella cheese. Spread 1 cup of the reserved spaghetti sauce over the bottom of a 9 x 13-inch pan prepared with nonstick cooking spray. Layer 5 to 6 noodles over the sauce and spread half the cheese mixture over the noodles. Spoon half the meatball mixture over the cheese. Repeat layers once. Add one more layer of 5 to 6 noodles and spoon remaining spaghetti sauce over top. Drizzle remaining water over top.
- Cover tightly with heavy-duty aluminum foil. Bake for 55-60 minutes, or until lasagna is fork tender. Sprinkle remaining cheese over top. Bake, uncovered, 5 minutes more. Let stand 5 minutes before serving.