In the bowl of standing mixer fitted with a whisk attachment, combine the butter, confectioner's sugar, salt, vanilla, and milk and whisk on medium-low speed until smooth.
Increase speed to medium-high and beat until light and fluffy, about 4 minutes.
To store, place a sheet of plastic wrap over the buttercream so that it is touching it, cover tightly with a lid, and freeze up to 1 month. Thaw in the refrigerator and rewhip before using.
Recommended for the Chipper Chocolate Cupcakes.
Recipe Source: From SWEET DESIGNS by Amy Atlas. Copyright (C) 2012 Amy Atlas and The Stonesong Press, LLC. Published by Hyperion. Available wherever books are sold. All Rights Reserved.