Bring a large pot of water to a boil and cook the 16-ounce package refrigerated cheese tortellini according to package directions. Drain and set the tortellini aside.

While the tortellini cooks, heat 1 tablespoon of the olive oil in a large nonstick skillet over medium-high heat.

Add the 1 1/2 pounds peeled and deveined shrimp to the hot skillet, sprinkle with 1 teaspoon cajun or creole seasoning, and cook about 1–2 minutes per side, just until the shrimp turn pink on the outside and are slightly translucent in the center (slightly undercooked). Remove the shrimp to a plate.

Add the remaining 1 tablespoon olive oil to the same skillet and reduce heat to medium. Add 1/2 medium diced yellow or sweet onion, 1/2 diced red bell pepper, and 8 ounces sliced smoked sausage. Cook, stirring occasionally, until the sausage is browned and the onion and bell pepper are soft, about 5–7 minutes.

Add 2 minced garlic cloves to the skillet and cook, stirring, for about 1 minute, until fragrant.

Pour in 1/2 cup butter and 1 cup heavy cream, then add 1/4 teaspoon dried thyme. If using, add 1/4 teaspoon cayenne pepper. Bring the mixture to a gentle simmer and cook, stirring occasionally, about 5 minutes, until the sauce thickens slightly.

Stir in 1/2 cup freshly grated Parmesan cheese until it melts into the sauce.

Return the shrimp to the skillet and cook 1–2 minutes more, just until the shrimp are fully opaque and cooked through.

Add the drained tortellini to the skillet and gently toss to coat and heat through, about 1–2 minutes.

Remove from heat, sprinkle with 1 tablespoon chopped fresh parsley, and serve.