Preheat oven to 400°F.
Boil spaghetti in salted water until al dente. Drain and set aside.
In a skillet, melt butter over medium heat. Add garlic and cook 1 minute. Stir in cream and seasonings. Reduce heat to low and slowly stir in Parmesan until melted and smooth.
Toss Alfredo sauce with cooked spaghetti in a 9x13 dish.
In a skillet, brown beef with onion and green pepper. Drain grease. Stir in spaghetti sauce, water, seasonings, and sugar.
Pour meat sauce over pasta (don’t stir). Top with mozzarella.
Bake uncovered 15–20 minutes or until bubbly. Garnish with parsley and serve.
