How to Make It
Beurre Monté can be made in any amount using the same cooking method. Bring the water to a boil in an appropriate size saucepan. Reduce the heat to low and begin whisking the butter into the water, bit by bit, to emulsify. Once you have established the emulsion, you can continue to add pieces of butter until you have the quantity of beurre monté that you need (the French Laundry makes 20 pounds at a time). It is important to keep the level of heat gentle and consistent in order to maintain the emulsification.
Make the beurre monté close to the time it will be used and maintain it in a warm place. If you have extra beurre monté, it can be refrigerated and reheated to use as melted butter or it can be clarified.