Season steak with pepper. Wrap fat around sides of steak, covering them completely but leaving top and bottom exposed. Tie fat to steak with string near top and also near bottom. Fat must be securely anchored to steak. Mix salt and water to make a paste. Mound about 3/4 of mixture over top of steak,covering meat completely. Put steak under broiler and broil 8 to 10 minutes depending on size of steak.
Carefully remove salt crust, keeping it in one piece. Turn steak over and place salt crust on other side. If needed, patch crust with remaining salt mixture. Broil steak another 8 to 10 minutes.Remove steak from boiler and discard crust and fat. Slice met, cutting slightly n the diagonal. Heat butter in chafing dish or large skillet til foaming and lightly browned. Put a few slices of meat at a time in butter and cook to desired degree of doneness. Allow about 1 minute on each side for rare. meat. Put each slice of meat on a slice of toast and spoon some of the hot butter over. Makes 2 servings.