Cut the potatoes into even sized pieces and place in a large pan of salted water. Bring to the boil and simmer until tender, around 20 – 25 minutes. Drain the potatoes well, return them to the saucepan and shake over a low heat for 30 seconds to remove some of the steam.
Heat the butter, milk and cream in a separate saucepan until the butter is just melted. Mash the potatoes with a masher and add the butter mixture, mixing in well until creamy and fluffy.
Season to taste with nutmeg, sea salt and black pepper.