Boil eggs hard. Cut slice off the end, so that the egg will stand firm. Dip egg in French dressing, then with a pastry bag arrange sardellen butter on the top of egg. Have ready small squares of toasted bread, spread with a thin layer of sardellen butter, on which to stand the eggs. Caviar, mixed with some finely chopped onion, pepper and lemon juice, may be used instead of the sardellen butter, but mayonnaise must be used over the caviar.