Legend has it that it was at this iconic New York City steakhouse that the first order of eggs Benedict appeared. Whether or not it is the truth, the restaurant still serves the dish in full fashion, with elegant touches like caviar and a brioche bun.
Whisk the egg yolks, lemon juice, Tabasco sauce, and Worcestershire sauce in a stainless steel bowl over a double-boiler of lightly simmering water, until the eggs have doubled in volume. Slowly drizzle in the clarified butter while continuing to whisk vigorously until the sauce has thickened. Season with salt and pepper and keep in a warm place until ready for use. If the sauce thickens add a few drops of water.
Lightly brush the brioche rounds with room-temperature butter. Toast till golden brown on both sides.
In a medium nonstick skillet lightly brown prosciutto cotto rounds and keep warm.
Fill a 10-inch skillet half full with water, add ¼ cup white vinegar, and bring to slow boil, then reduce to a low simmer. Slowly break the eggs, 1 at a time, into the water and cook until egg whites have set, about 3 minutes. Remove the eggs with slotted spoon and drain.
Place the warm toasted brioche rounds on plate, top with prosciutto cotto, place the poached eggs on prosciutto, and top with hollandaise sauce. Garnish with Osetra caviar.