Cook the fettuccine in a large pot of salted boiling water according to package directions until al dente; drain and set aside.
In a saucepan over medium heat, melt the butter, then add the minced garlic and cook, stirring, until fragrant, about 1 minute.
Whisk in the flour until combined, then gradually whisk in the milk. Continue whisking and cook until the sauce thickens and is smooth.
Lower the heat and stir in 1 cup of the Parmesan, the reduced-fat cream cheese, and the salt until the cheeses melt and the sauce is creamy.
Add the hot cooked fettuccine to the sauce and toss to coat evenly.
Serve immediately, sprinkled with the remaining Parmesan, chopped parsley, and freshly ground black pepper to taste.