Season and cook the chicken in a pan over medium heat until golden and fully cooked, then allow it to rest before slicing to keep it juicy.
Boil the fettuccine in salted water until al dente, reserving some pasta water to adjust the sauce later.
Prepare the sauce by sautéing garlic in butter, then adding cream and letting it gently simmer to develop richness.
Stir in parmesan cheese off high heat, ensuring it melts smoothly into a creamy, lump-free sauce.
Combine pasta and sliced chicken with the sauce, using reserved pasta water as needed to achieve the perfect consistency.
Garnish with parsley and extra cheese, and serve immediately for the best texture and flavor.