Bring a large pot of salted water to a boil and cook the rigatoni according to package instructions until al dente, about 10-12 minutes. Drain and set aside.

Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the Italian sausage and brown for 6-8 minutes, breaking it up as it cooks.

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

Pour in crushed tomatoes, heavy cream, and chicken broth. Stir in Italian seasoning and red pepper flakes, then season with salt and pepper. Simmer on low for 10 minutes.

Add the cooked rigatoni to the skillet and gently stir to coat the pasta in the sauce.

Sprinkle grated Parmesan cheese over the pasta and stir gently until melted and incorporated into the sauce.

Ladle into bowls and garnish with fresh basil leaves. Serve hot.