Hollandaise is a classic French sauce produced by the emulsification of butter, lemon and egg yolks which are seasoned with a little salt and cayenne pepper. Some recipes suggest vinegar as apposed to the lemon juice, while some also include a little water with the egg yolk. A normal ratio of ingredients for Hollandaise is 1 egg yolk to 1 teaspoon of water, 1 teaspoon of fresh lemon juice, 4 tablespoons of unsalted butter and a pinch each of fine salt and cayenne pepper.