Marinade the fillet with Madeira for 2–3 hours; drain well, coat it with Matignon and envelop it completely with thin slices of salt pork fat.
Tie carefully with string and braise it in the marinade together with some Rhine wine. A few minutes before being required for service, untie the string, remove the fat and Matignon and glaze the fillet.
Place it on a long dish and surround with separated bouquets of small Quenelles of veal and butter forcemeat containing chopped red tongue, moulded with teaspoons; thick slices of foie gras cooked in butter; fine cockscombs; very white button mushrooms; and large olive-shaped truffles. Place 1 large decorated Quenelle of the same forcemeat on each side of the fillet.
Remove all the fat from the braising liquid, pass firmly through a fine strainer, reduce by two-thirds and add some Sauce Demi-glace.
Coat the bouquets of garnish excepting the two large Quenelles, with some of the sauce and serve the rest separately.