1. Cook the Pasta: Start by cooking the ziti pasta according to the package instructions until it’s al dente. Drain the pasta and set it aside.

2. Prepare the Sausage: In a large skillet, heat the olive oil over medium-high heat. Add the chopped onion and minced garlic, and sauté until they become translucent and fragrant.

3. Brown the Sausage: Remove the sausage from its casing and crumble it into the skillet with the onions and garlic. Cook the sausage until it’s browned and cooked through, breaking it apart into small pieces with a wooden spoon.

Make the Marinara Sauce: Stir in the crushed tomatoes, dried basil, dried oregano, crushed red pepper flakes, salt, and black pepper into the skillet with the sausage mixture. Simmer the sauce for about 10-15 minutes, allowing the flavors to meld together.

5. Preheat Your Oven: While the sauce simmers, preheat your oven to 375°F (190°C).

6. Assemble the Ziti: In a large mixing bowl, combine the cooked ziti, ricotta cheese, and 1 cup of shredded mozzarella cheese. Mix well until the pasta is evenly coated.

7. Layer the Dish: In a 9×13-inch baking dish, spread a thin layer of the marinara sauce on the bottom. Add half of the ziti mixture as the next layer. Top this with half of the remaining marinara sauce, followed by half of the grated Parmesan cheese.

8. Repeat the Layers: Repeat the layering process with the remaining ziti mixture, marinara sauce, and Parmesan cheese. Finish by sprinkling the remaining mozzarella cheese evenly over the top.

9. Bake to Perfection: Cover the baking dish with aluminum foil and bake in the preheated oven for 25-30 minutes. Then, remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden brown.

10. Serve and Enjoy: Allow your baked ziti to cool for a few minutes before serving. Garnish with fresh basil leaves if desired.