Quick update: I had the fettuccine alfredo leftovers tonight and to help thicken the sauce, I added cornstarch and it worked miracles. I literally googled "how to thicken sauce" and found a random website with directions. So, I used a tablespoon of cornstarch for every cup of sauce, added a bit of water to the cornstarch to make it a thin paste, added the corn starch mixture to the sauce on the stove top, let it simmer to activate the corn starch and voila! Thickened sauce. Perfection.