Entrecote With Oysters And Piquant Sauce

750 g entrecote steak
500 g shallots, very finely chopped
1 liter vinegar
Salt
48 medium-sized oysters, opened
Dijon-type mustard

Place the shallots in a casserole on the stove. Add the vinegar. Boil for about 30 minutes until almost all the liquid has disappeared. The sauce, in the form of a puree of shallots, is now ready. Grill the entrecote. Sprinkle it with salt. Serve each person with a generous piece of meat, a few spoonfuls of sauce and a dozen oysters. The ritual for eating the dish is as follows. Take a mouthful of entrecote with sauce, with or without a good mustard. As soon as this is done, swallow an oyster. The sensation of cool freshness that succeeds the fire of the piquant sauce is indescribable.