In a large pot, bring salted water to a rolling boil. Add rigatoni and cook according to package instructions until al dente, about 10-12 minutes.

In a spacious skillet, heat olive oil over medium heat, then add Italian sausage, breaking it into pieces. Cook for 5-7 minutes until browned.

Add diced onion and minced garlic to the skillet with sausage. Sauté for about 3-4 minutes until onion is translucent.

Pour in crushed tomatoes, heavy cream, and chicken broth, stirring to combine. Add Italian seasoning and red pepper flakes, then season with salt and pepper.

Allow the sauce to simmer for about 10 minutes, stirring occasionally.

Stir in the drained rigatoni, ensuring each piece is coated in the creamy sauce. Heat through for another 2-3 minutes.

Sprinkle grated Parmesan cheese over the rigatoni mixture and stir until melted and well incorporated.

Spoon the creamy rigatoni onto plates and garnish with fresh basil leaves. Serve hot.