Cook the Pasta: Follow package instructions to cook rigatoni until al dente. Drain and set aside.
Brown the Sausage: In a large skillet, heat olive oil over medium heat. Add garlic sausage and cook, breaking it up with a spoon, until browned and thoroughly cooked.
Add Garlic: Add minced garlic to the skillet and cook for an additional 1 minute, stirring constantly to avoid burning.
Create the Sauce: Pour in the heavy cream and bring to a simmer. Let it cook for 2–3 minutes until it starts to thicken. Stir in the grated Parmesan cheese until melted and the sauce is smooth. Season with salt and pepper to taste.
Combine with Pasta: Add the cooked rigatoni to the skillet and toss until the pasta is well coated in the creamy Alfredo sauce.
Serve & Garnish: Serve hot, garnished with chopped fresh parsley and extra Parmesan if desired.