Boil the chicken according to preceding recipe. Mince the meat fine. Make a sauce by putting into a saucepan one Tablespoonful of butter, and as it melts add one onion, minced very fine; a sprig of minced parsley, one minced bay leaf, and a half clove of minced garlic. Let it simmer gently without browning and then add one Tablespoonful of flour, well sifted. Mix thoroughly, and add three tablespoonfuls of vinegar or a wineglass of White Wine. Stir well and add one pint of the water in which the Chicken was boiled. Season with salt and pepper to taste and a slight dash of Cayenne. Then add one Tablespoonful of prepared mustard. Let simmer three minutes longer, and as it comes to a boil, pour over the Chicken and serve.