Cook the Rigatoni
Bring a large pot of salted water to a boil. Cook the rigatoni according to package directions until al dente. Before draining, reserve about 2 cups of the starchy pasta water. Drain the pasta and set it aside.

Brown the Sausage and Aromatics
In a large Dutch oven or heavy-bottomed pot, heat the olive oil over medium-high heat. Add the sausage and cook, using a spoon to break it apart, until it is well-browned. Add the diced onion and cook for 4-5 minutes until softened. Stir in the minced garlic and cook for one more minute until fragrant.

Build the Sauce
Pour in the tomatoes, fresh or dried basil, fresh or dried oregano, red chili flakes, salt, and pepper. Stir everything together and allow the sauce to simmer for about 10 minutes, letting the flavors meld. If using whole tomatoes, crush them with your spoon against the side of the pot.

Make It Creamy
Reduce the heat to low and slowly pour in the heavy cream, stirring until combined. Add the grated Parmesan cheese and continue to stir gently until the cheese has completely melted and the sauce is smooth and velvety.

Combine and Serve
Add the cooked rigatoni to the sauce. Toss well to ensure all the pasta is evenly coated. If the sauce seems too thick, add a splash of the reserved pasta water until it reaches your desired consistency. Serve immediately, garnished with extra Parmesan and fresh basil if desired.