Heat 1 dl (3½ fl oz of ½ U.S. cup) oil in a pan; add a Mirepoix comprising 125 g (4½ oz) carrot, 125 g (4½ oz) onion, a pinch of thyme, half a crushed bayleaf, a few parsley stalks and 1 kg (2¼ lb) of trimmings of venison; cook until well coloured and drain off the oil. Moisten with 3 dl (½ pt or 1¼ U.S. cups) vinegar, 2 dl (7 fl oz or ⅞ U.S. cup) white wine and reduce completely.
Add 1 litre (1¾ pt or 4½ U.S. cups) Sauce Espagnole, 2 litres (3½ pt or 9 U.S. cups) brown game stock and 1 litre (1¾ pt or 4½ U.S. cups) marinade; cover with a lid and cook slowly in the oven, if possible, for 3½–4 hours. Eight minutes before passing the sauce add 12 crushed peppercorns; pass firmly through a sieve and add 2½ dl (9 fl oz or 1⅛ U.S. cups) brown game stock and 2½ dl (9 fl oz or 1⅛ U.S. cups) marinade. Simmer again gently, skimming as necessary for approximately 40 minutes so as to reduce the sauce to 1 litre (1¾ pt or 4½ U.S. cups). Pass through a fine strainer and finish with 75 g (2½ oz) butter.