Preparation Club Sandwich:
Chop the cocktail onions finely and stir into the hollandaise sauce. Lay a lettuce leaf on a slice of Schär multograin bread, spread with one tablespoon of the sauce, cover with 1 tablespoon caviar, several slices of the hardboiled egg, and one slice of the salmon, and cover with the second slice of bread.
Cover this once again with the same ingredients and then top off with the third slice of bread.
Preparation hollandaise sauce: With a wooden spoon, beat the egg yolks with one tablespoon of water in a dish with a thick and concave bottom.
Heat the container in a bain marie (double boiler) over boiling water and add half of the butter. Stir quickly until the butter has melted and slowly add the remaining butter alternating with some cold water and lemon juice, mix well, and add salt.
Simmer in the bain marie over a low heat until the sauce thickens and becomes creamy.