Step 1: Cook the linguine. Bring a large pot of salted water to a rolling boil. Add the linguine and cook according to package directions until al dente. Before draining, reserve 1 cup of the starchy pasta water. Drain the linguine and set aside.
Step 2: Prepare the chicken. While the pasta cooks, pat the chicken pieces dry and season generously with salt and pepper. In a large skillet over medium-high heat, melt 1 tablespoon of the butter. Add the chicken and cook for 5-7 minutes, stirring occasionally, until browned and cooked through. Remove the cooked chicken from the skillet and set aside.
Step 3: Make the Cowboy Butter sauce. Reduce the heat to medium. Add the remaining 7 tablespoons of unsalted butter to the same skillet. Once melted, add the minced garlic, smoked paprika, chili powder, and cayenne pepper. Sauté for 1-2 minutes until fragrant.
Step 4: Combine and finish. Stir in the lemon juice and the 1/4 cup of fresh chopped parsley into the butter mixture. Return the cooked chicken and drained linguine to the skillet. Toss everything together, adding the reserved pasta water a quarter cup at a time until the sauce reaches your desired creamy consistency. Taste and adjust seasoning with additional salt and pepper if needed.
Step 5: Serve immediately. Garnish generously with extra fresh parsley and a sprinkle of grated Parmesan cheese, if desired. Enjoy your flavorful Cowboy Butter Chicken Linguine!