Cut the bread into small cubes. Grate the cheese on the Bircher grater to the bread. Boil the water and pour it over the bread and cheese. Cover and let stand for half an hour.
In the meantime, remove the skin from the onion and chop finely. In a caquelon, saute in half the butter until light yellow. Remove and set aside.
Add the remaining butter to the caquelon form. Briefly fry the bread and cheese in it.
At the same time, in a second frying pan, bring the milk to a boil. Add to the bread and cheese mixture. Season lightly with salt and make on low fire for 5 minutes, stirring continuously. Sprinkle with the onion and bring to the table on the spot.
Tables. Everybody helps himself from the caquelon piece by piece, similar to the fondue.