Step 1: Cook the Rigatoni

1. Bring a large pot of salted water to a rolling boil.
2. Add the rigatoni pasta and cook according to package instructions until al dente.
3. Reserve ½ cup of pasta water, then drain and set aside.

Step 2: Cook the Sausage

1. In a large skillet or pan, heat olive oil over medium heat.
2. Add the Italian sausage (remove from casings if using links) and cook, breaking it apart with a spatula, until browned and fully cooked (about 5-7 minutes).
3. Remove excess grease if necessary, but leave about 1 tbsp of fat for extra flavor.

Step 3: Sauté Aromatics

1. Add minced garlic, chopped onions, and red pepper flakes (if using) to the pan.
2. Cook for about 2-3 minutes, stirring occasionally, until the onions are soft and fragrant.

Step 4: Build the Sauce

1. Stir in tomato paste and cook for 1 minute to deepen the flavor.
2. Add crushed tomatoes, chicken broth, and Italian seasoning, then stir to combine.
3. Pour in the heavy cream and mix well. Reduce heat to low and let it simmer for 5 minutes.
4. Stir in Parmesan cheese, butter, salt, and black pepper. Mix until smooth and creamy.

Step 5: Combine with Pasta

1. Add the cooked rigatoni to the sauce, tossing well to coat each piece in the creamy mixture.
2. If needed, add reserved pasta water a little at a time to adjust the consistency.
3. Let it simmer for 2 more minutes to marry the flavors.

Step 6: Serve and Garnish

1. Remove from heat and sprinkle with freshly chopped basil or parsley.
2. Serve hot, topped with extra Parmesan cheese.