Shred the parmesan cheese and set aside to allow it to come to room temperature.
Boil a large pot of salted water. Once boiling, add the fettuccine noodles and cook according to the package instructions until they are al dente.
Melt the butter in a large skillet over medium heat. Sprinkle in the flour and whisk for about thirty seconds until it becomes a light golden color.
Add the minced garlic to the skillet and cook for another thirty seconds, being careful not to let it burn.
Slowly whisk in the heavy cream and milk, bringing the mixture to a gentle simmer.
Once simmering, remove the skillet from the heat and stir in the shredded parmesan cheese a handful at a time, stirring until the cheese is completely melted and the sauce is smooth.
Season the sauce with Italian seasoning, salt, and pepper to taste.
Once the pasta is cooked, reserve about a cup of the pasta water. Then, using tongs, transfer the cooked fettuccine directly into the skillet with the sauce.
Toss the noodles in the sauce to coat them evenly. If the sauce is too thick, add a bit of the reserved pasta water until you reach your desired consistency.
Garnish your Fettuccine Alfredo with freshly chopped parsley and an extra sprinkle of parmesan cheese on top, if desired. Serve hot and enjoy!