Bring a large pot of salted water to a boil.
Cook the linguine according to package directions until al dente.
Drain and set aside.
Heat olive oil in a large skillet over medium-high heat.
Add the chicken in a single layer.
Season with paprika, garlic salt, kosher salt, and black pepper.
Cook for 3–4 minutes without stirring until golden brown.
Add 2 tablespoons of cowboy butter to the skillet.
Flip the chicken and continue cooking for another 3–4 minutes until the internal temperature reaches 165°F (74°C).
Transfer the chicken to a plate and keep warm.
Reduce heat to low.
Add the remaining cowboy butter, heavy cream, garlic salt, and red pepper flakes to the skillet.
Stir while scraping up the flavorful browned bits from the pan.
Once the butter is melted and the sauce is smooth, add the cooked linguine.
Return the chicken to the skillet.
Toss until everything is evenly coated in the creamy sauce.
Stir in the lemon juice.
Serve the Cowboy Butter Chicken Linguine immediately garnished with lemon slices and fresh parsley.