In a saucepan combine the yolks, lemon juice and water, over low heat. Whisk to combine.
Once the mixture gets warm slowly add the cold butter in one piece at a time, whisk to incorporate, continue with all the butter.
Season to taste with salt and white pepper.
Set aside until ready, when ready to use return to a low heat and drizzle in hot water, just enough to warm and make a smooth sauce if sauce has gotten to thick.