Bring a large pot of water to a boil and cook tortellini according to package directions.
Heat 1 tablespoon oil in a large nonstick skillet over medium-high heat. Add the shrimp and sprinkle the cajun seasoning over them. Cook just until the shrimp turn pink and remove them from the pan. Note: The shrimp will cook a little more when you add them to the tortellini, so if anything you want them slightly undercooked when you remove them from the pan.
Add the remaining olive oil to the skillet along with the onion, bell pepper and sausage and cook until the sausage is browned and the onion and bell pepper are soft, about 5 to 7 minutes.
Add the garlic and cook 1 minute.
Add the butter, heavy cream, and thyme. (If using, add the cayenne.) Simmer for about 5 minutes to thicken.
Stir in the parmesan cheese and then add the shrimp.Check for seasoning and add salt and pepper to taste.
Finally, stir in the tortellini and sprinkle with parsley.
Notes
For the smoked sausage, I like to use kielbasa. If you want additional spice, use andouille.