About 1 cup
You can make hollandaise in a blender (see the variation), but the stovetop version is perhaps a little finer and pretty much foolproof. Depending on how you’re using it, you can stir about 1 teaspoon minced fresh tarragon, 1 tablespoon fresh dill or chervil, or some other herb into the finished sauce.
3 egg yolks
6 tablespoons (¾ stick) butter, softened and cut into tablespoons
1 teaspoon fresh lemon juice
Pinch cayenne (optional)
1. Put the yolks in a small saucepan with 2 tablespoons water and a pinch salt; turn the heat to very low and cook, whisking constantly, until light, foamy, and slightly thickened. (If at any point during this process the yolks begin to curdle, immediately remove from the heat and continue to whisk for a minute before returning the pan to the stove.)
2. Remove from the heat and stir in the butter, a tablespoon or 2 at a time. Return to the heat and continue to whisk until the mixture is thick and bright yellow. Whisk in the lemon juice, then taste and adjust the seasoning (add the cayenne now if you’re using it) and serve. (If you like, you can keep the finished sauce warm over extremely low heat or—better—over very hot water, for 15 or even 30 minutes, whisking occasionally.)
Melt the butter in a small saucepan over low heat or in the microwave; do not let it brown. Combine the egg yolks, salt, lemon juice, and cayenne if you’re using it in the blender and turn on the machine. Slowly drizzle in the butter; the mixture will thicken. Taste and add more lemon juice or other seasonings if necessary.