Fish is cleaned and put on the grill for steaming. Around her rank carrots, onion - chopped in two, potatoes - chunks. On the bottom of the container put water and steam cooker. To prepare the sauce warm butter in it and fry the flour. Add a little of the broth and yogurt with broken yolks. Boil for 5-6 minutes. Season with lemon juice, nutmeg, salt and pepper. Fish and vegetables are placed in a large bowl and pour the sauce.