Bring a large pot of salted water to a boil. Add the fettuccine and cook according to package directions until al dente, about 8-10 minutes. Drain and set aside, reserving about 1 cup of pasta water.

While the pasta cooks, season the chicken breasts with salt and pepper. In a large skillet over medium-high heat, melt 2 tablespoons of butter. Add the chicken and cook for about 6-7 minutes on each side, or until the internal temperature reaches 165°F and the meat is golden brown. Remove the chicken from the skillet and let it rest for a few minutes before slicing it into strips.

In the same skillet, melt the remaining 2 tablespoons of butter over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.

Pour in the heavy cream, stirring well. Bring it to a gentle simmer, allowing it to thicken slightly for about 3-4 minutes.

Reduce the heat to low and gradually whisk in the grated Parmesan cheese until the sauce is smooth and creamy. If the sauce is too thick, add some reserved pasta water, one tablespoon at a time, to reach your desired consistency. Season with salt and pepper to taste.

Add the cooked fettuccine to the sauce, tossing to coat. If necessary, add more pasta water for creaminess. Lastly, fold in the sliced chicken.

Serve the Chicken Fettuccine Alfredo immediately, garnished with chopped parsley for a pop of color.