1. Cook the rigatoni according to package instructions until al dente. Drain and set aside.
2. In a large skillet, heat olive oil over medium heat. Add the sliced sausage and cook until browned, about 5 minutes. Remove from the skillet and set aside.
3. In the same skillet, add the chopped onion, minced garlic, and sliced bell pepper. Sauté until the onion is translucent and the peppers are tender, about 4-5 minutes.
4. Stir in the heavy cream, chicken broth, and Cajun seasoning. Bring the mixture to a simmer, allowing it to thicken slightly, about 3-4 minutes.
5. Add the cooked rigatoni and browned sausage back into the skillet. Toss to coat the pasta and sausage in the creamy sauce.
6. Stir in the Parmesan cheese until melted and well combined. Season with salt and pepper to taste.
7. Garnish with chopped parsley if desired, and serve hot.

A little tip from my kitchen: If you want a thicker sauce, let it simmer a bit longer. And remember, tasting as you go is the key to balancing flavors!