4 tournedos (4 2cm-thick slices of tender fillet)	salt
20 g butter
4 tablespoons of dry white wine
For the Bercy butter:
2 shallots (finely chopped)	1/2 tablespoon of parsley (finely chopped)
8 tablespoons of dry white wine	the juice of 1/4 of a lemon
60 g butter	salt and pepper
100 g marrow

Buy 5 or 6 3-4cm long pieces of bone with marrow. Put them in a dish, and the dish on a saucepan with little boiling water and heat them for a few minutes to extract the marrow.

Weigh 100 g marrow and put it in a small saucepan. Cover with slightly salted cold water and bring slowly to the boil. Simmer for 5 minutes. Then drain the marrow and cut into small pieces.

Put the shallots in a saucepan with 8 tablespoons of wine and simmer for about ten minutes; then increase the flame to reduce the liquid to a tablespoon. Remove from the heat.

Add the shallots when the saucepan is still hot with 60 g butter cut into pieces and mix until it softens. Add the marrow, parsley, salt, plenty of pepper, the lemon juice and mix. Pour the sauce into a sauceboat. Leave to cool out of the fridge.

Remove the fat, skin and nerves from the fillet. If you want to change them into tournedos, tie them at half the thickness with a string.

Heat 20 g of butter in a pan; when it has finished foaming and has started to get brown, add the tournedos. Heat them for 2-3 minutes on each side. If you want them well-done simmer for further 4-5 minutes, turning them frequently without piercing them.

Put them in a hot serving dish. Put 4 spoons of wine in the pan, add some salt and heat for a few minutes. Put the sauce on the tournedos; on each of them put 1/2 tablespoon of bercy butter and serve.