Perfect prep ahead side dish. Bake just before serving for piping hot mashed potatoes!
Preheat oven to 350° F.
Peel and cut potatoes. Place in a pan of cold water, bring to a boil and cook for approximately 15 minutes or until fork tender.
Let the butter and cream cheese come to room temperature and cut into cubes.
Drain boiled potatoes and place in a large bowl. Mash the potatoes and add in all ingredients except the Parmesan cheese. Combine all ingredients well.
Place the mashed potatoes into a buttered baking dish and top with Parmesan cheese. Bake for 30 minutes and serve immediately.
Prep option: When completely cooled, cover the casserole and place in fridge. To reheat, remove from fridge and let sit an hour at room temperature. Preheat oven to 350° F and heat for approximately 20-30 minutes.