How to Make It
In a blender, combine the egg yolks, lemon juice, cayenne, and ½ teaspoon salt and blend until frothy.
Heat the butter in a small saucepan over medium heat until bubbling (do not let it brown). With the blender running, remove the center cap from the lid and add the hot butter in a thin stream, blending until thickened. If the sauce is too thick, add warm water, 1 tablespoon at a time, to achieve the desired consistency.
Note: Because the eggs in this recipe are not cooked, there is a risk of food-borne illness.