Using a wide pan over medium heat, melt the butter. Add garlic and cook 30 seconds until fragrant.
Pour in chicken broth and milk. Season lightly with salt and pepper. Add dry fettuccine and press it down so it's mostly covered.
Bring pasta to a gentle simmer. Cook 10–12 minutes, stir it very often until pasta is tender and sauce thickens.
Lower the heat and add in Parmesan until it is creamy and smooth.
Taste, adjust seasoning to liking, and top with parsley and parmesan.
