Cook spaghetti according to package directions for al dente pasta. Reserve ½ cup pasta water then drain the spaghetti and set aside.

Heat olive oil in a large skillet, with deep sides, over medium heat. Add sliced sausage and cook until browned, stirring occasionally, about 5 minutes. Remove the sausage from the skillet and reserve.

To the same skillet add onion, bell pepper, celery, Cajun seasoning and kosher salt and cook until the vegetables begin to soften, about 5 minutes, stirring occasionally.

Add the garlic and cook for 1 minute.

Pour in diced tomatoes and tomato sauce and bring to a boil. Reduce the heat to medium-low and simmer for 10 minutes.

Stir in the heavy cream and reserved pasta water and simmer for an additional 2 minutes.

Add the cooked spaghetti and reserved sausage to the skillet, tossing until evenly coated.

Sprinkle with Parmesan cheese and chopped parsley.