Fill a large pot with salted water and bring to a boil. Add the rigatoni and cook for 8-10 minutes until al dente. Reserve 1 cup of pasta water, drain rigatoni.

In a large skillet, heat olive oil over medium heat. Add diced onion and sauté for about 4-5 minutes until translucent.

Stir in minced garlic and sauté for an additional minute until fragrant and golden.

Crumble in Italian sausage and cook for 6-8 minutes until browned and fully cooked.

Add canned tomatoes to the skillet, breaking them up. Simmer for about 15 minutes.

Stir in red chili flakes, salt, and pepper. Adjust according to taste.

Gradually pour in heavy cream while stirring. Allow to thicken for 5-7 minutes.

Stir in grated Parmesan cheese until fully melted. Adjust consistency with reserved pasta water if needed.

Add cooked rigatoni to the skillet and gently toss to coat in the creamy sauce.

Serve hot, garnished with additional Parmesan and fresh basil.