Bring a large pot of salted water to a rolling boil. Add rigatoni and cook according to package instructions until al dente. Drain and reserve 1 cup of pasta water.

In a large skillet, heat olive oil over medium heat. Add the Italian sausage, breaking it up as it cooks for 5-7 minutes until browned.

Add chopped onion to the skillet and sauté for 3-4 minutes until soft. Incorporate minced garlic and red pepper flakes, cooking for an additional minute.

Stir in crushed tomatoes and simmer for about 10 minutes until the sauce thickens.

Lower the heat and stir in heavy cream. Simmer for an additional 5 minutes until thickened.

Add the drained rigatoni to the sauce and toss until well coated, adding reserved pasta water if too thick.

Sprinkle in Parmesan cheese and stir until melted. Season with salt and pepper as desired.

Garnish with fresh basil and serve immediately.