Bring a large pot of salted water to a boil over high heat. Add the cheese tortellini, cooking according to the package instructions until al dente, typically about 3-5 minutes. Reserve ½ cup of pasta water, then drain the tortellini and set aside.

Pat the sirloin or ribeye steak dry with paper towels to ensure a good sear. Season both sides generously with Cajun seasoning, salt, and black pepper. Heat 2 tablespoons of olive oil in a large skillet over medium-high heat, then add the steak, searing for 2-3 minutes on each side until browned and cooked to your desired doneness. Once cooked, transfer the steak to a plate and let it rest.

In the same skillet, reduce the heat to medium and add 6 tablespoons of unsalted butter. Once melted, toss in the minced garlic and sauté for about 1-2 minutes until fragrant. Stir in the red pepper flakes, Dijon mustard, and lemon juice, allowing the flavors to meld.

Return the cooked tortellini and sliced steak to the skillet. Toss everything together, coating the tortellini and steak in the buttery sauce. Gradually add the reserved pasta water, stirring until you achieve a silky consistency. Mix in the freshly chopped parsley, chives, and grated Parmesan, letting the cheese melt into the dish.

Plate the Cowboy Butter Tortellini Steak Bites while hot, garnishing with extra Parmesan, chopped parsley, and a sprinkle of Cajun seasoning. Enjoy!