Mashed potatoes are best when served fresh. They are rather hard to effectively reheat, and while microwaving works, it still requires rather frequent stirring to achieve an evenly heated dish. This dish is a perfect solution for situations when you may wish to prepare the potatoes ahead of time and just pop them in the oven for a shirt period of time before the meal.
2 lb cooked potatoes
0.5 cup milk
4 tbsp butter
0.5 cup grated Parmesan
0.5 cup grated mozzarella
Mash the cooked potatoes and mix with the milk and butter. Add most of the mozzarella and Parmesan. Season with salt and black pepper.
Distribute the mix into a glass baking dish. Sprinkle remaining cheese on top. Bake uncovered in a 400F oven for about 20 minutes. Serve!