Chop the onion finely and stew in heated butter. The washed and cleaned chicken, pour 1 liter of cold water and boil on medium heat. When the water boils, remove the foam and add stewed onions and cleaned and cut into rings carrot. When cooked, boned meat, cut into small pieces and return to broth until it is cooked. Add crumbled vermicelli and after about 10 minutes the soup bind with beat egg yolks with the flour. Season with lemon juice, salt and pepper.