Depending on how you plan to decorate your cake, you might need to make two batches of icing. The single batch should cover and fill the whole cake with a thin layer buttercream. Or it will give you a thick filling and thick layer on top, leaving the sides bare. I made two batches to ensure I had enough for the ruffles on top. For the second batch, I substituted the cocoa powder for a teaspoon of vanilla extract and some food colouring paste.