Grate two ounces of cheese and mix it smoothly in a bowl with a dessertspoonful of mustard, the same of anchovy sauce, a shake of cayenne, a pinch of salt, a dessertspoonful of anchovy vinegar, a tablespoonful of fresh butter, and the yolks of two hard-boiled eggs. Mix this until it is a smooth paste, then spread it on rounds of buttered white or brown bread. Chop the whites of the eggs finely, or press them through a sieve on the paste. Serve cold.