Chocolate buttercream icing can be made by combining 3 sticks softened butter, 5 cups confectioners' sugar, 1 cup cocoa, 1/2 cup milk and vanilla. In general, chocolate icing can be made by starting with a standard icing recipe and adding 1 cup unsweetened cocoa or 2 blocks unsweetened baker’s chocolate.
FSW Insider describes six types of icing that include chocolate, including buttercream, whipped cream, cream cheese frosting, boiled or cooked icing, glaze, ganache and fudge icing. The site also includes descriptions of royal icing and fondant, which are not suitable chocolate icing options because they are primarily for cake decorating and focus on creating a suitable consistency for piping and rolling rather than adding flavor.
To get fast results with fewer ingredients, try ganache or chocolate whipped cream icing. Ganache contains only chopped chocolate and heavy cream. Chocolate whipped cream icing only calls for three ingredients: 2 cups whipping cream, 1 cup confectioners’ sugar and 1/4 cup cocoa. For a richer flavor, try Natasha’s Kitchen chocolate cream cheese frosting, an option that is also easy to make, using 8 ounces cream cheese, 1/2 cup butter, 3 cups confectioners' sugar, 1/2 cup unsweetened cocoa powder, 1/4 teaspoon salt and 1 teaspoon vanilla.