The freezed peace is drained and passed through a cold water jet. The onion is peeled, washed, cut into slices and braised. The milk is boiled and chilled. The eggs are washed, disinfected, passed trough a cold water jet. The egg yolks are separated from the albumens. The bread is cut into cubes which are sprinkled with butter and browned in the oven, obtaining the croutons. The flour is bolted.
The onion is soaked in oil and water. The peace is added, the water, salt and the dissolved flour; everything is boiled until the peace is well done. Everything is blended until we obtain a cream. The egg yolks are mixed with milk and salt and they are poured into the cream, continuously mixing it so as it does not cut. Small pieces of butter are added.