Soften butter in a small saucepan (or within the microwave utilizing a microwave protected dish.) Stir in cocoa powder, combination will type a thick paste.
Switch chocolate combination to a medium dimension mixing bowl. With mixer on low pace, add in powdered sugar, milk and vanilla.
As soon as components are integrated, flip mixer to medium excessive pace and beat about 5 minutes, till frosting is easy and creamy. Unfold on prime of cooled cake.
