Beefsteak with Oysters

This is a sauce recipe with a steak attached: the original assumes you know how to broil a steak and gives its attention to the oyster gravy poured over it. The hinge is restraint at the stove, since oysters held past the moment they plump turn tough.

• "1 steak"No weight or cut is given. A thick sirloin, porterhouse or strip steak of about 2 lb serves four with this quantity of sauce; broil or pan-sear it and let it rest while the oysters cook.
• A quart of oystersThat means shucked oysters with their liquor, roughly 2 lb; the count varies with size, anywhere from about three to five dozen. They are often sold in pint or half-pint tubs, so you may need two or more.
• "A very little of their juice"Drain the oysters and keep only a few tablespoons of liquor in the pan. Too much and the sauce will be thin and briny rather than buttery.
• The butter and flourRubbing sifted flour into soft butter makes what is now called beurre manié. Add it in small pinches, stirring until each is dissolved, or it will sit in lumps.
• Timing"When they come to a boil" is effectively the whole cooking time for the oysters: they are done as soon as the edges ruffle, one to two minutes. The further minute of boiling would also serve to cook out the raw flour, so add the butter-flour paste promptly.
• The scumThe grey foam that rises is coagulated protein and bits of shell grit. Skimming it is worth the ten seconds; it is the difference between a clean sauce and a cloudy one.
• SeasoningNone is specified. Salt cautiously at the end, since oyster liquor is already salty, and a good deal of black pepper suits the dish.
• ServingServes four. Carve the steak across the grain, pour the oysters and sauce over the slices, and bring it to the table immediately; the sauce breaks and cools quickly.