Put the beef into a roasting tin without any fat. Sprinkle beef with pepper. Roast in a hot oven, 425°F, 220ଌ, gas mark 7 for fifteen minutes. Lower heat to 375°F, 190°C, gas mark 5 for the rest of cooking time, allowing fifteen minutes to the pound. Baste meat frequently with pan juices. Beef should be served underdone, and should be transferred to a heated dish and left to rest for fifteen minutes before carving.
To make the Yorkshire Pudding, sieve flour and salt together into a mixing bowl. Add the eggs and stir into the flour. Add half the milk slowly, and stir until the mixture is smooth. Add the remaining milk slowly and beat batter well, and then beat in the cold water. Fifteen minutes before the beef is cooked, pour two tablespoons of its fat into a ten inch square tin. Put tin into the oven, and when fat is sizzling hot, pour in the pudding batter. Bake at the top of oven for thirty minutes (the meat is removed fifteen minutes earlier to rest before carving). The pudding should be well-risen, puffy, crisp and brown on top and bottom, and should be served straight from the tin in which it is baked, cut in squares.
If fresh horseradish is to be used for the Horseradish Sauce, the root should remain in cold water for one hour, then be washed well, and scraped into very thin shreds with a sharp knife. If bottled horseradish is used, it must be drained and squeezed dry in a kitchen towel. To make the sauce, whip the cream to stiff peaks, and fold in the horseradish, sugar, mustard, salt, pepper and vinegar. Serve cold.