Most (but not all) traditional recipes ask you to use unsalted butter, but we don't think that's your problem.

Traditional Hollandaise Sauce is made with melted butter. Since the salt stays with the milk solids that fall to the bottom of the container when the butter is melted, it is very easy to avoid the salt. Skim off any foam from the top of the melted butter and either pour the melted fat off into another container before you start adding it to the sauce (leaving the milk solids and salt in the bottom of the pan), or pour the fat carefully into the sauce (so that you are easily able to stop before inadvertently adding the milk solids and salt).

What causes most early-stage Hollandaise sauces to break, however, is adding too much butter too quickly. When the recipe says "add by drops" (which is what it should say), it means it. If you pour even a thin stream of melted butter into the egg-yolk mixture at the beginning, your sauce is likely to break.

Almost everyone who has made Hollandaise Sauce more than a couple of times gets cocky and thinks (or worse, says), "My Hollandaise sauce has never broken. I'll add the butter a little more quickly this time." The result is a humbling experience. Do not get cocky; do not add the butter in a stream, however small. Add a drop or two, incorporate it thoroughly; add another few drops, incorporate; and only after you have repeated the process several times and the sauce has clearly "taken," can you progress to pouring in a thin stream of butter, while whisking vigorously.

If your sauce breaks (separates into a liquid butter and egg-yolk mess), there are a few possible solutions. The first is to thoroughly whisk another egg yolk in a separate container, and then – drop by drop – add your broken sauce to the new egg yolk. Once that has been incorporated, you can go on mixing in the rest of the butter. Another option is to whisk in a half-teaspoon or so of Dijon mustard, which has emulsifiers that will bring the egg and butter together. You can find many Hollandaise recipes that already include as insurance a bit of Dijon mustard. The mustard is no shrinking violet, however, and we are not enamored of the taste change it brings to Hollandaise Sauce. You can also stir in 1 to 2 tablespoons of chilled cream, but we do not find it as effective as the mustard thing.

Some people have had such unhappy experiences making Hollandaise Sauce the traditional way, that they have switched to other methods, which, while perhaps more reliable, do not produce equally magnificent results. It being your choice, however, we gladly make available recipes for Microwave Hollandaise Sauce and Blender Hollandaise Sauce.