In a large pot, bring salted water to a rolling boil over high heat. Once boiling, add the rigatoni pasta and cook until al dente, about 10-12 minutes. Before draining, reserve a cup of the starchy pasta water to adjust the sauce’s consistency later. Drain the pasta and set it aside.

Heat a large skillet over medium heat and drizzle in the olive oil. Add the spicy Italian sausage, using a spatula to break it into smaller chunks. Cook for 5-7 minutes, until browned and cooked through. Remove the sausage from the skillet and set it aside.

In the same skillet, add the diced onion and sauté for about 3-4 minutes until translucent. Stir in the minced garlic and cook for an additional minute until fragrant.

Introduce the cubed butternut squash to the skillet with dried thyme and crushed red pepper flakes. Sprinkle in salt and pepper to taste, and stir. Cook for approximately 8-10 minutes until the squash is tender.

Reduce heat to low and slowly pour in the heavy cream, stirring to prevent curdling. Allow to simmer for 2-3 minutes until thickened slightly.

Return the cooked sausage to the skillet, stirring to incorporate. Add reserved pasta water as needed to reach desired consistency.

Add drained rigatoni into the skillet, tossing gently to coat in sauce. Fold in the grated Parmesan cheese until melted and well combined.

Taste the dish, and adjust the seasoning with more salt and pepper if necessary. Serve hot, garnished with freshly chopped parsley.