While capable of forming emulsions, cooked egg yolks are far less efficient emulsifiers than raw. To circumvent this problem, include a raw egg yolk to make the sauce easier to emulsify. Although this sauce is traditionally served with cold fish, its tangy acidity works well with deep-fried foods (even french fries). Both the whites and yolks of hard-boiled eggs are used. Prepare a mayonnaise base with 3 sieved hard-boiled egg yolks, 1 raw egg yolk, 1 tablespoon (15 milliliters) mustard, 1 tablespoon (15 milliliters) wine vinegar, 1 teaspoon (5 milliliters) fine salt, pepper to taste, and 1 cup (250 milliliters) safflower oil. Make sure the mixture is worked to a smooth paste before adding the oil. Add 2 tablespoons (30 milliliters) chopped capers, 2 tablespoons (30 milliliters) chopped sour gherkins (cornichons), and 2 tablespoons (30 milliliters) mixed chopped fresh parsley, chervil, and tarragon. (If all three are not available fresh, do not substitute dried herbs; just add a little more of the other two.) Finish the sauce with a julienne of the 3 cooked egg whites.