Peel and cut up two good-sized onions, put them in stewpan with an ounce of butter, till they are a nice yellow color, then add eight tablespoonfuls of demi-glaze, and two of water or broth; skim, boil quickly; when of a proper thickness add a good tablespoonful of French mustard; season rather high, if no French mustard, use English, but French is preferable as it adds to the flavor.