Created by BusyMiz on December 10, 2014
Step 1: Whisk together first 5 ingredients in a small saucepan. Cook over medium heat, whisking constantly, 5 minutes or until thickened. Spoon mixture into a small bowl; cover surface of mixture with plastic wrap, pressing wrap onto surface, and let stand 30 minutes or until cool.
Step 2: Beat butter and sugar at medium speed with an electric mixer until light and fluffy. Gradually add cooled cocoa mixture, 1 tablespoon at a time, beating until blended after each addition. Add vanilla, beating until mixture is the consistency of whipped cream.