Some recipes for chocolate icing include a classic chocolate icing from Food Network, and bourbon chocolate icing from Alton Brown. Both recipes take less than 15 minutes to make.
To make classic chocolate icing, sift 3 cups of confectioner's sugar together with 3/4 cup of unsweetened cocoa. In another bowl, take 1 cup of the sugar and cocoa mixture, a stick of softened butter and a tablespoon of heavy cream, beating it until smooth. Add another cup of the mixture and an additional tablespoon of cream, and continue until adding all of the mixture. If needed, also add another tablespoon of cream before beating in a teaspoon of vanilla and then spreading it on a cake.
To make the bourbon chocolate icing, put 12 ounces of unsalted butter and an ounce of mayonnaise in a stand mixer and beat for about four minutes. With the mixer on low, slowly pour in 6 ounces of semi-sweet melted chocolate, scraping the sides as needed. Turn off the mixer and take a pound of powdered sugar, mixing in a cup at a time. When all of the sugar is in the bowl and mixed, add 2 tablespoons of bourbon and a pinch of kosher salt, and then beat until smooth. Use the icing immediately or refrigerate up to a week.