Potatoes Peel. Several potatoes are cut to length so as to obtain sufficient ellipses, with which to cover the bottom of the baking pan. Other potatoes are cut into slices. Mix the milk, cream, broth, mustard and half the Parmesan in a large saucepan and boil. Add a few pinches of nutmeg, add salt and add the potatoes. When the liquid boils again, the pot was capped and allowed to simmer for about 6 minutes. Using the clamps are removed elongated potato slices and set aside. Other potatoes with milk sauce is poured into a tray and top lining separated potato slices tightly, as overlap. Sprinkle with remaining grated Parmesan and a pinch of nutmeg. Heat the oven to 180 C and bake gratin 1 hour. Then degrees increase of 200 and bake another 15 minutes until the top is golden brown crust forms.