The sauce is a warm and rich yellow in colour and boasts a thick and smooth texture. The end result should be a delicious combination of butter and egg yolks with a tangy twist of lemon and a touch of spice.
Although the sauce has few ingredients, it does have a reputation of being very difficult to make. This is because the traditional method involves whisking the lemon juice into the beaten egg yolks, whilst cooking gently over simmering water.
The temperature of the water here is everything, because if there is too much heat, the eggs will scramble and overcook. On the other hand, if the water is not hot enough, the sauce may separate. Therefore this has to be a slow and steady process that cannot be rushed.
The second thing to watch out for is the process of adding the butter (preferably clarified butter). This must be done a little at a time, whilst continuously whisking and if too much butter is added at once, the sauce may not thicken.
Egg yolks can only cope with absorbing a certain amount of butter overall, so if too much butter is incorporated, the sauce will eventually curdle. Try to stick to using no more than 3 oz (85 g) of butter for each egg yolk and this problem should not occur.
Nowadays, the sauce can be partly made in a food processor or blender, which removes some of the difficulties from preparing the sauce and potentially leaves less room for disaster.
Once you have grasped and mastered how to make Hollandaise sauce, you could also try to prepare some of the other sauces that are derived from this French classic.
By adding a handful of capers, a delicious "sauce aux capres" is created, the addition of whipped cream gives "Mousseline Sauce", whilst in order to transform Hollandaise sauce into a delicious "Béarnaise Sauce" to be served with steak, you will need to add a few chopped shallots, some white wine vinegar and a teaspoon of dried tarragon
Below are several recipes for Hollandaise sauce ranging from the simplest method to the more traditional methods that require a bit more work.