Method
Heat the water in a pan over a medium heat, add the chocolate powder and whisk for about a minute until smooth.
Beat in the egg yolks, then remove from the heat.
Add the icing sugar and mix in thoroughly.
Beat in the butter a portion at a time, until melted.
Once all the butter is incorporated, place the pan in a bowl of cold water and beat the mixture until it is light and thick enough to spread.
Use to decorate your cake.
