The Unexpected Ingredient That Will Majorly Upgrade Your Hollandaise Sauce

Hollandaise sauce is one of the five foundational sauces of classic cooking — and if you haven't tried it, you're missing out.

Hollandaise sauce dates back to 1651, when it appeared in the French cookbook "Le Cuisinier François." But the version of the sauce that we know now was reborn after World War I when the French dairy industry all but dried up. The French government imposed heavy rations on the public, decreeing that no milk or fresh cream could be served in restaurants after nine in the morning, per The Food Historian. This put an end to many of France's typically rich milk products and required that they import their butter from Holland. As such, what was once known as Sauce Isigny — named after a dairy-producing region in Normandy — became Hollandaise sauce, per the Online Etymology Dictionary.

Today it is one of the five mother sauces: veloute, Espagnole, tomato, béchamel, and Hollandaise sauce. And as such, it serves as a base for secondary sauces such as foyot, choron, maltaise, and béarnaise sauce, among others, per The Spruce Eats. If you've got the classic Hollandaise sauce down pat, here's how to make it even better.

A standard Hollandaise sauce is a simple yet delicate combination of clarified butter and warm egg yolk. Though a rich combination, the pairing is still somewhat plain on the palate. Because of this, the average hollandaise sauce will also contain salt, lemon juice, and black pepper. The latter constitutes the typical Hollandaise sauce, but some variations contain unexpected ingredients, such as Dijon mustard. 

Dijon mustard contributes to a consistent texture in Hollandaise sauce and promotes flavor. According to recipe developer Ting Dalton, "Just a tiny teaspoon really lifts the flavor of the Hollandaise." Dalton's Hollandaise sauce recipe contains all the standard ingredients, plus Cayenne pepper and Dijon mustard.

Bear in mind: The success of a well-made Hollandaise sauce is equally dependent on its methodology. Warm the egg yolk while slowly stirring in the clarified butter, advises The Spruce Eats. From there, you can upgrade it with whatever ingredients you see fit — Dijon mustard included.