Brown the sausage or ground beef in a large nonstick skillet. When fully cooked, add the jar of spaghetti sauce and stir until heated through. Keep warm.
Melt the butter and sprinkle with flour. Slowly add the heavy cream and 1/4 cup of pasta water. Stir 1 cup of parmesan cheese. Season with salt and black pepper.
Combine the Alfredo sauce with the cooked pasta and place in the baking dish. Pour the red sauce over the top and top with mozzarella and remaining parmesan cheese.