Peel potatoes. In a large pot, boil potatoes until tender. Drain water and mash potatoes using a potato masher or beat them using a mixer. Mix in cream cheese, butter, garlic, mozzarella, salt, and pepper until completely potatoes are creamy.
Pour potatoes into a casserole dish. Sprinkle Parmesan cheese on top. Bake for 15 minutes (or until there's a light brown crust on top) on 375 degrees F.
Recipe by Sophistishe at http://sophistishe.com/2013/12/cheesy-garlic-mashed-potatoes/