1. Bring a large pot of salted water to a boil and cook ziti until al dente, 1–2 minutes less than package directions. Drain and set aside.

2. In a large skillet, heat olive oil (if needed) over medium-high heat. Add sausage and cook until browned, breaking it apart with a spoon.

3. Add onion and cook until softened, then stir in garlic and cook for 30 seconds.

4. Stir in tomato paste, crushed tomatoes, and marinara sauce. Add basil, oregano, red pepper flakes, salt, and pepper. Simmer for 10 minutes.

5. Preheat oven to 375°F (190°C). In a large bowl, mix cooked pasta with half of the sauce and half of the mozzarella.

6. Spread a thin layer of sauce in a 9×13-inch baking dish. Layer half the pasta, dollops of ricotta, and a sprinkle of Parmesan. Repeat layers and top with remaining sauce and mozzarella.

7. Cover with foil and bake for 20 minutes. Remove foil and bake 10 more minutes until bubbly and golden.

8. Let rest 5–10 minutes before serving. Garnish with fresh parsley or basil.