A little bit of water helps the emulsion process: Whether you emulsify 4 tablespoons (2 ounces) or 1 pound of butter, just a tablespoon of water will do. Any amount of beurre monte can be made using the following method. Read the particular recipe through to determine the total amount of Beurre Monte you will need.
Bring the water to a boil in an appropriate-size saucepan. Reduce the heat to low and begin whisking the chunks of 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 monte that you need (we make 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 Monte close to the time it will be used and keep it in a warm place. If you have extra Beurre Monte, it can be refrigerated and then reheated to use as melted butter or clarified.
Though we are enamored of Beurre Monte and use it all day in our kitchens, when a recipe calls for only a tablespoon or two, you can substitute whole butter.