butter. Put the egg yolks and lemon juice in a bowl in a bain-marie and
beat hard until the eggs start to thicken. Then remove from the
bain-marie and beat in the melted butter drop by drop, as for
mayonnaise. Beat continuously while adding the butter. Add salt and a
few drops of lemon juice to taste, and stand the sauce in a bain-marie
until needed. This sauce cannot be re-heated.