Hollandaise Sauce
This rich yet airy, velvety sauce is made by enriching an acidic liquid with egg yolks and then thickening with butter. Here, we used a wine reduction, but you can skip that step and simply whisk eggs with 1 teaspoon lemon juice and 1/4 cup boiling water. As one of the French “mother sauces,” its preparation is a basic culinary technique that can be varied to create other sauces in the same family (often referred to as “warm emulsions”). By changing the acidic liquid to blood orange juice and zest, you get sauce Maltaise, typically served over steamed asparagus; tangerine juice and zest flavor Mikado sauce. Perhaps the best-known variation is Béarnaise, a traditional accompaniment for steak. To make it, prepare the hollandaise as directed, adding tarragon (the defining flavor of Béarnaise) to the reduction mixture. As it is designed to demonstrate, the method is the key to making the sauce, not the specific ingredients used to give it flavor. When making hollandaise or any of its variations, using gentle heat is critical to achieving the right consistency. The best—and classic—way to do this is to “cook” it in a bain marie, or hot-water bath, instead of directly over a burner.