01 - Heat a large heavy-bottomed pot over medium-high heat. Add spicy Italian sausage and cook, breaking apart with a wooden spoon, until thoroughly browned.
02 - Add onion to the sausage and cook until softened, about 3 minutes. Stir in garlic and crushed red pepper flakes; sauté until fragrant, approximately 1 minute.
03 - Pour in tomato pasta sauce and chicken broth. Mix until combined, scraping any browned bits from the bottom of the pot.
04 - Stir in uncooked rigatoni, ensuring pasta is fully submerged in liquid.
05 - Bring mixture to a gentle boil, then reduce heat to medium-low. Cover and simmer for 15–18 minutes, stirring occasionally, until pasta is al dente.
06 - Uncover the pot. Stir in heavy cream, shredded mozzarella, and grated Parmesan until cheeses melt and sauce is creamy. Season with salt and black pepper.
07 - Sprinkle chopped fresh basil over the pasta and serve immediately.