Cook the Pasta: Bring a large pot of salted water to a rolling boil. Add rigatoni and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water, then drain.

Sauté the Sausage: In a skillet, heat olive oil over medium heat. Add spicy sausage, breaking it up, and cook for 5-7 minutes. Transfer to a plate.

Sauté Onions and Garlic: In the same skillet, add onion and sauté for 3-4 minutes until translucent. Add garlic and cook for another minute.

Cook the Butternut Squash: Add butternut squash, thyme, red pepper flakes, salt, and pepper. Cook for 8-10 minutes until tender.

Add the Cream: Pour in heavy cream and simmer for 2-3 minutes until slightly thickened.

Combine Ingredients: Return sausage to the skillet and stir to combine. If sauce is too thick, add reserved pasta water gradually.

Mix in the Pasta: Add drained rigatoni and toss to coat with the creamy sauce. Stir in Parmesan cheese until melted.

Final Seasoning and Serve: Taste and adjust seasoning if needed. Serve garnished with fresh parsley.