1. Preheat oven to 400°F (or set broiler to high if finishing under broiler).

2. Cook rigatoni in salted boiling water until al dente. Drain and set aside.

3. In a large skillet, brown the ground beef and Italian sausage. Drain any excess fat.

4. In the same skillet, melt butter and sauté minced garlic for 1–2 minutes.

5. Pour in heavy cream and simmer for 3–5 minutes, stirring occasionally.

6. Stir in Parmesan cheese until melted and the sauce thickens slightly.

7. Add salt, pepper, and red pepper flakes to taste.

8. Combine cooked pasta, meat, optional spinach, and half the mozzarella into the sauce. Stir well.

9. Pour mixture into a baking dish and top with remaining mozzarella and a sprinkle of Parmesan.

10. Bake for 10–15 minutes until bubbly and golden brown.