Melt the milk couverture in the oven at 88° to 90°F/31.1° to 32.2°C, or use tempered couverture.
In a bowl, blend the butter by hand with a spatula until smooth.
Mix the butter and couverture together by hand using a spatula or a stand mixer fitted with the paddle attachment. The closer the temperatures of the butter and the couverture, the easier it