Add the ground beef, chopped onion, garlic and bell pepper to a large skillet. Brown the ground beef and vegetables together, breaking the beef into small pieces as cooks. Drain any excess fat and season with salt, pepper, garlic powder and Italian seasoning.
Stir in the tomato sauce and simmer for about 5-10 minutes.
Toss the cooked spaghetti into the Alfredo sauce and add it to a greased 9” x 13” baking dish. Spread it out so that it's flat and even.
Spoon the tomato sauce and beef mixture to the top and sprinkle with Parmesan cheese and shredded mozzarella cheese.
Top the beef mixture with Parmesan cheese and shredded mozzarella cheese. Finally, place it into the center rack of the oven, uncovered, for about 20 minutes or until the cheese is melted and the sides are hot and bubbly. Let rest for 5-10 minutes and enjoy!