We heat a pan of water on the stove. When it comes to a boil, we turn off the heat, and move the pan to a cool part of the stove. In a blender, we mix the egg yolks, the lemon juice and the salt and pepper. We blend this for 25 seconds and then with the motor running we drizzle in the melted butter a drop at a time. We do not want to go too fast with the butter, or the sauce will not be creamy. After about 1/4 cup of the butter is incorporated, we pour the rest in a slow stream. We pour the mixture into a bowl. We put this bowl into the pan of hot water to keep the sauce warm while we prepare the eggs.