The potatoes are peeled, washed and cut into slices. The onion is peeled, washed, cut into slices and soaked in boiled water. The eggs are washed, disinfected, passed trough a cold water jet. The egg yolks are separated from the albumens. The milk is boiled and chilled. The white bread is cut into cubes which are browned in the oven and sprinkled with butter.
The onion and the potatoes are braised in butter. Water is added and they are boiled at moderate flame so as not to stick to the pan. When the tomatoes are boiled they are kept. The milk, the egg yolks and salt are mixed with flour and added to the cream; they are boiled for 10 more minutes, on the top we add pieces of butter.