1. Prepare the cowboy butter: In a medium bowl, whisk together softened butter, minced garlic, lemon juice, lemon zest, parsley, chives, smoked paprika, onion powder, garlic powder, cayenne, salt and pepper until smooth and evenly blended. Divide the mixture—set half aside for basting and sauce, and use the other half to coat the chicken.

2. Marinate the chicken: Toss the chicken strips in half of the cowboy butter until fully coated. Let rest at room temperature for 10–15 minutes (or refrigerate up to 2 hours for deeper flavor).

3. Cook the pasta: Bring a large pot of salted water to a boil. Add linguine and cook according to package instructions until al dente. Drain, reserving ½ cup of pasta water, and set both aside.

4. Sear the chicken: Heat olive oil in a large skillet over medium-high heat. Add the marinated chicken strips in a single layer. Cook without moving until golden on one side, about 3–4 minutes, then flip and cook another 2–3 minutes until cooked through. Transfer chicken to a plate and tent with foil to keep warm.

5. Sauté the veggies: In the same skillet, add onion and bell peppers. Cook, stirring occasionally, until softened and edges begin to brown, about 4 minutes. Add mushrooms and garlic and sauté another 2–3 minutes until mushrooms release their juices and garlic is fragrant.

6. Build the sauce: Pour in chicken broth to deglaze the pan, scraping up any browned bits on the bottom. Stir in heavy cream, Parmesan cheese and the reserved cowboy butter. Bring to a gentle simmer, stirring constantly, until the sauce thickens slightly, about 2 minutes. Taste and season with salt and pepper as needed.

7. Combine and finish: Return the cooked chicken to the skillet along with drained linguine. Toss gently to coat everything in the creamy sauce, adding a splash of reserved pasta water if you prefer a looser texture.

8. Garnish and serve: Sprinkle with extra chopped parsley and an extra grating of Parmesan if desired. Serve immediately while hot.