Bring a large pot of salted water to a boil and cook the tortellini according to the package directions until tender but still al dente. Reserve ½ cup of pasta water before draining.

Pat the steak pieces dry with paper towels and season them with Cajun seasoning, smoked paprika, garlic powder, salt, and black pepper.

Heat olive oil in a large skillet over medium-high heat and sear the steak bites for about 2–3 minutes on each side until browned. Remove from skillet and let them rest.

In the same skillet, reduce the heat to medium and melt the butter. Add the minced garlic and stir until fragrant.

Stir in red pepper flakes, Dijon mustard, and lemon juice, followed by chopped parsley and chives.

Return cooked tortellini and seared steak bites to the skillet, mixing into the sauce, adding reserved pasta water as needed for consistency.

Stir in grated Parmesan cheese until melted and creamy.

Serve hot, garnished with additional Parmesan, parsley, and a sprinkle of Cajun seasoning if desired.