Skin, slice, and mince quickly two pounds’ weight of the white part only of some fine mild onions, and stew them in from two to three ounces of good butter over a very gentle fire until they are reduced to a pulp, then pour to them three-quarters of a pint of rich veal gravy; add a seasoning of salt and cayenne, if needed; skim off the fat entirely, press the sauce through a sieve, heat it in a clean stewpan, mix it with a quarter of a pint of rich boiling cream, and serve it directly.