Bring a large pot of water to a boil. Add about 1 tablespoon of salt and pasta. Cook according to package directions. Reserve 1/2 cup of pasta liquid and then drain pasta.
If sausage is in casings, remove them. Cook the sausage in a large skillet, crumbling it as it cooks.
Remove sausage from skillet and set aside. Add a drizzle of olive oil to the skillet and cook the onion and bell pepper until soft.Add garlic and cook 30 seconds.
Add diced tomatoes, heavy cream, cajun seasoning, cayenne pepper, and black pepper. Simmer for a few minutes.
Add sausage and pasta to skillet and stir into sauce. Add reserved pasta liquid if the pasta is too dry.