The chocolate icing recipe for this pound cake is made using dark chocolate with a high percentage of cocoa butter, which means it is bitter. The bitterness of the chocolate is balanced by the sweetness of the sugar. To ensure the chocolate icing is not too sweet, use dark chocolate with 70% or more cocoa butter. And if you still find that too sweet, you can replace 1 tablespoon of powdered sugar with cocoa powder. Cocoa powder will stiffen the icing, and to make it into smooth spreadable consistency, you will also need to add some cream or milk to the icing. Start with one tablespoon and increase gradually to achieve the desired consistency for your icing.