Peel the potatoes with a potato peeler or a small kitchen knife. Wash thoroughly and dice coarsely. Cover the potatoes and cook them in about 2 l boiling salted water for about 25 minutes.
In the meantime, heat the milk and cream in a small pot while stirring (do not bring to the boil). Melt butter in it while stirring. Stir in 1⁄2 tsp salt, 1 pinch of pepper and 1⁄2 tsp nutmeg.
Take it off the stove.
Drain the potatoes. Add warm milk mixture to the cooked potatoes.
Mash the potatoes well with a potato masher until the liquid is completely mixed. Season the puree again with salt and nutmeg.