Chicken cut into pieces and fry gently in the butter. After removing the fat in sauté until soft chopped onion and celery, diced. Sprinkle with flour, stir several times, pour hot water or broth and boil. Add the meat, then add salt dish and leave to simmer. When the meat is tender, add chopped parsley and a few minutes later - black pepper, lemon juice and yogurt with broken egg.