Baked Mashed Potatoes with Parmesan Cheese

Preheat oven to 400 degrees. Coat a 13 by 9 by 2-inch baking dish with 1 tablespoon of butter and set aside. Cook the potatoes in a large pot of boiling salted water until they are very tender, about 15 minutes. Drain, return the potatoes to the same pot and mash well. Mix in the milk and melted butter. Mix in the mozzarella and ¾ cup of the Parmesan. Season, to taste, with salt and pepper. Transfer the potatoes to the prepared baking dish. Stir the bread crumbs and remaining ¼ cup of Parmesan in a small bowl to blend. Sprinkle the bread crumb mixture over the mashed potatoes. Recipe can be prepared up to this point 6 hours ahead of time, cover and chill. Bake, uncovered, until the topping is golden brown, about 20 minutes.