Preheat oven to 375°F (190°C).
Peel and dice the potatoes.
Boil potatoes until tender.
Drain and mash the potatoes.
Mix in the butter and cream.
Season with salt, pepper, and nutmeg.
Spread in a greased baking dish.
Sprinkle grated Parmesan on top.
Bake for 30 minutes.
Let cool before serving.
