Fish is cleaned from the viscera and skin and wash. In a suitable container boil water, which added carrot slices, shredded celery, chopped onion, bay leaf, black pepper and salt. After making the marinade boil, place fish boil 15-20 minutes. Boiled fish is placed in the appropriate plateau bay made with sauce and place slices of lemon. Serve garnished with boiled potatoes. Preparation of sauce: yolks are broken down in a tube placed in a water bath over low heat while added the broth of fish. When the mixture becomes creamy mass is removed from the fire. Trickle add the melted butter. Sauce add salt and add the lemon juice.