Cook the rigatoni according to package instructions until al dente.
In a large skillet, heat some olive oil over medium heat and add the chopped onion and minced garlic.
Add the Italian sausage to the skillet, breaking it apart with a wooden spoon as it cooks.
Once the sausage is thoroughly cooked, pour in the heavy cream and broth, and stir to combine.
Stir in the Italian seasoning, grated Parmesan, and season with salt and pepper.
Toss the cooked rigatoni into the sauce, making sure each piece is well-coated.
Garnish with fresh parsley before serving.