Boil a salted pot of water for the pasta. Cook the rigatoni dente according to package directions.
Meanwhile, saute the sausage meat and onion over medium-high heat in a skillet until browned (about 8-10 minutes), stirring it occasionally.
Stir in the garlic and cook for 1 minute.
Drain a bit of the fat from the pan
Add the canned tomatoes to the pan. Simmer the sauce for 10 minutes (you may need to turn the heat down a bit if it starts bubbling too furiously).
Stir in the cream, basil (if using), and season the sauce with salt & pepper as needed. Cook for another minute or two and then toss with the drained pasta.