Crumble half of Million Dollar Pound Cake into a large bowl. Microwave chocolate baking bar and cream in a medium-size microwave-safe bowl at HIGH 1 to 1 1/2 minutes or until melted and smooth, stirring at 30-second intervals. Stir in instant coffee. Stir Vanilla Buttercream Frosting and chocolate mixture into cake until mixture holds its shape. Shape into 1-inch balls. Roll each truffle in cocoa 2 times.