Cut 60 g (2 oz) onion and 80 g (3 oz) raw ham into fine Paysanne; place 40 g (1½ oz) butter in a pan, add the Paysanne and cook to a light brown colour. Moisten with 1½ dl (5 fl oz or ⅝ U.S. cup) vinegar, add a Bouquet garni and reduce almost completely.
Add 3 dl (½ pt or 1¼ U.S. cups) Sauce Espagnole and simmer gently for 15 minutes, skimming carefully. Remove the Bouquet garni and finish the sauce with ¾ dl (3 fl oz or ⅜ U.S. cup) port and a good tbs redcurrant jelly.
This sauce is an excellent accompaniment for joints of venison.