Ken uses jaune d’Arbois wine in this dish. If you cannot find it, use half the quantity of the best rich, but dry, sherry you can buy. He uses sea beans as part of the garnish.
Bring the water to a simmer, squeeze in the juice from the lemons, and then over medium heat whisk in ½pound of the butter in pieces until they are all incorporated into a smooth emulsion. Remove from the heat and season with salt and white pepper to taste.