The day before, remove the meat and the real fillets from the bone. Use the real fillets for another dish. Clean the remaining meat carefully all around, cut the thin ends into small pieces.
Chop the bones into pieces and put them in a roasting pan with the leftover meat.
Clean, rinse and coarsely chop the greens. Peel and quarter the onion. Put everything into the roasting pan, place on the 2.
Put everything into the roaster, put it on the second shelf from the bottom into the preheated oven and roast it at 250 °C for thirty to forty minutes until it is dark brown.
Put the roaster on the stove top and deglaze the roasted ingredients with the water. Dissolve well all the roasting substances on the wall and bottom. Add bay leaf, a little salt and a few peppercorns and simmer gently for an hour and a half at a mild temperature. Pour through a muslin cloth into a measuring cup: half of the original amount of liquid should remain. Leave to cool for one night .
A day later, soak the gelatin in cold water. Degrease the stock, pour it into a saucepan, retaining the cloudy sediment. Warm the stock slightly, season with salt, Madeira and vinegar. Allow the dripping gelatin to melt at a mild temperature and stir into the stock.
Pour a stock level into small porcelain molds (125ml capacity) and set in the refrigerator. In the meantime, rub the meat not too sparingly with salt on all sides and cook in not too hot clarified butter for four to five minutes on each side.