Cook the pasta: Bring a large pot of salted water to a boil. Add rigatoni and cook according to package directions until al dente. Drain and set aside, reserving about 1/2 cup of the pasta water to adjust the sauce later if needed.
Cook the sausage: Heat olive oil in a large skillet over medium-high heat. Add the Italian sausage, breaking it apart with a spatula as it cooks. Sauté until browned and cooked through, about 6–8 minutes. Drain any excess fat for a lighter sauce.
Sauté the aromatics: Add the diced onion and minced garlic to the skillet with the cooked sausage. Sauté for 2–3 minutes, stirring occasionally, until the onion becomes soft and fragrant.
Build the sauce: Stir in the tomato sauce and reduce the heat to medium-low. Add the heavy cream and simmer gently for 4–5 minutes until the sauce thickens slightly. Stir in the garlic powder, onion powder, salt, pepper, and Italian seasoning. The combination of tomato and cream creates a perfectly balanced, silky sauce.
Incorporate the pasta: Add the drained rigatoni to the skillet and toss well to coat each piece in the creamy sauce. Stir in the grated Parmesan, allowing it to melt into the sauce for extra richness. If the sauce is too thick, add a splash of the reserved pasta water to loosen it slightly.
Garnish and serve: Remove from heat and transfer to serving bowls. Sprinkle with freshly chopped parsley and extra Parmesan cheese before serving. Enjoy hot for the best texture and flavor.
