Heat butter in a large skillet over medium high heat. Add garlic and cook, stirring frequently, until fragrant, about 1-2 minutes.
Add in the chicken broth, milk, and fettuccine. Season with salt and pepper.
Bring the pot to a boil, then reduce heat and simmer, stirring occasionally, until pasta is cooked through, about 18-20 minutes.
Stir in Parmesan. If the mixture is too thick, add more milk as needed until desired consistency is reached.
Serve immediately, and top with parsley.
Original recipe called for 1 cup of milk. Adjust pasta cooking time as needed for the brand of pasta you are using.