Bring a large pot of generously salted water to a boil over high heat. Add the linguine and cook until al dente, about 9–11 minutes, stirring occasionally. Reserve ¼ cup of the pasta water before draining.

In a medium bowl, combine garlic powder, onion powder, paprika, cayenne pepper (if using), salt, and black pepper. Toss the spice blend over the cubed chicken.

In a large skillet, heat 2 tablespoons of olive oil and 1 tablespoon of butter over medium-high heat. Once the oil is shimmering, add the seasoned chicken and sear for 3–4 minutes on each side, until golden brown and cooked through. Transfer to a plate and cover with foil.

Without cleaning the skillet, reduce heat to medium-low and add the remaining tablespoon of butter. Allow to melt gently, then stir in the minced garlic and sauté for about 30–60 seconds.

Add chicken broth, lemon juice, and Dijon mustard to the skillet. Let simmer for 2 minutes, then stir in heavy cream and grated Parmesan until smooth. Continue simmering gently to thicken.

Return the seared chicken and any collected juices to the skillet, then add the cooked linguine. Toss until well coated with the sauce. If too thick, add a splash of reserved pasta water.

Turn off the heat and stir in freshly chopped parsley. Plate your Cowboy Butter Chicken Linguine, garnishing with additional parsley, cracked black pepper, and red pepper flakes. Serve with lemon slices.