Herring are cleaned, remove bones, acidified with lemon, add salt and cut into cubes. Chopped onion stew gently, add the flour, fry to a light and diluted with water so as to obtain a thickish sauce. Season with pepper and salt. Boil 10 minutes, add the sauce "Worcester", put the pieces of herring and leave on low heat to boil. Before presenting mix with yogurt and a tip of a knife grated lemon peel.