One of the mother sauces in French Cuisine, this sauce is usually a mixture of egg yolks, melted butter, and an acid (sometimes lemon juice, other times a vinegar or wine reduction). As implied by the composition, hollandaise sauce is an emulsion as well. Alterations can be made depending on the desired flavor profile.

Though the sauce is associated with French cuisine, and the first written recipe is French, the name hollandaise sauce translates to Hollandic sauce. This makes sense given that the name originated from the Franco-Dutch War of the 17th century. Further to the point of the last paragraph, that first recipe mentioned using nutmeg for the sauce.

One of the common dangers associated with execution of the sauce is the sauce being “broken”, meaning that the emulsion has been disrupted and has separated into the base components. Recommendations about what to do when this happens involve removing the sauce from heat, and whisk in a small amount of water and or cream. Other dangers include scrambling the egg yolks used in the sauce; if this happens, it was probably due to having the sauce on too high a heat. The end result is that the egg yolks coagulate, leaving a scrambled texture rather than the desired smooth texture.

As a mother sauce, there are many potential derivatives of hollandaise sauce. Popular derivatives include Béarnaise sauce, Girondine sauce, and Bavaroise sauce. All told, hollandaise sauce is very versatile.

However, there is a big drawback to the sauce depending on what you are wanting to use it for. Hollandaise sauce is best served fresh, but you can store it in the fridge. When you reheat the sauce, though, you will want to do so on a low heat, whisking the sauce constantly. If you do not wish to bother with the reheating and are going to use the sauce in short order, consider storing the batch in a thermos of some sort or over a bowl of warm water, not hot. Also, please make sure not to put the sauce in the water but a container holding the sauce in the water.

Before touching on popular use cases, I should add that there have been variations of hollandaise sauce that do not make use of eggs as an emulsifier. While this is not traditional in the strict sense of the word, there is a rich history of using alternatives, even in France. However, if you are pursuing alternatives due to the aforementioned challenges associated with a traditional hollandaise sauce, most people recommend practicing making the sauce; it should become easier over time.

Popular dishes that a hollandaise sauce is used in include asparagus dishes, eggs benedict (it is a key ingredient here), eggs Florentine, various crab dishes, and more. It can also be used with steak dishes as well and chicken. However, it is typically not associated with desserts, but that is not to say that it is impossible in the strict sense. I may simply be unaware of use cases (excluding surface similarities between the sauce and custards).