01 -
Place the softened butter, confectioners' sugar, milk, and vanilla extract into a stand mixer fitted with a whisk attachment.
02 -
Begin mixing on low speed to gradually blend the sugar with the butter.
03 -
Increase the mixer speed to high and whip for 5 minutes until the mixture doubles in volume, becoming very pale and fluffy.
04 -
Pause periodically to scrape down the sides of the bowl to ensure even mixing.