Peel the potatoes and put them in water for about 30 minutes to remove some of the starch.
In the meantime, rub the Dutch Oven with rapeseed or sunflower oil.
It is best to use a food processor to cut the potatoes into even, thin slices. Then lay them flat in the Dutch Oven and sprinkle some nutmeg between each layer or, better still, grate them fresh.
Put the cream and milk in a saucepan, season with salt, pepper and nutmeg to taste and bring to the boil briefly. Pour the hot sauce over the potatoes and then sprinkle with the grated Emmental and mountain cheese.
For an FT6 I use 18 coals, 4 below, 14 above.
The gratin is ready when the cheese is slightly browned. The cooking time is approx. 70 - 80 minutes.