Cook the Pasta:
Bring a large pot of salted water to a boil. Cook linguine according to the package directions until al dente. Drain and set aside.

Cook the Chicken:
In a large skillet over medium-high heat, heat the olive oil. Add chicken in a single layer and season evenly with paprika, garlic salt, kosher salt, and black pepper. Cook for 3 to 4 minutes without moving, until golden.

Finish the Chicken:
Add 2 tablespoons of the cowboy butter to the skillet. Flip the chicken and cook another 3 to 4 minutes, or until the internal temperature reaches 165°F. Remove the chicken from the pan and set aside, covering lightly to keep warm.

Make the Sauce:
Lower the heat to low. Add the remaining 2 tablespoons cowboy butter, heavy cream, garlic salt, and crushed red pepper flakes to the skillet. Stir, scraping up any browned bits from the bottom of the pan, until the butter has melted and the sauce is smooth.

Combine and Finish:
Return the cooked linguine and chicken to the skillet. Toss everything together to coat well. Stir in the lemon juice and mix until evenly combined.

Serve:
Plate the pasta and top with optional lemon slices and chopped parsley, if desired.