"This is a very delicate, all butter, chocolate buttercream icing. My husband, who is not a sweets eater, requests this icing on an orange cake each year for his birthday. Try it and you won't be disappointed."
Melt the chocolate over low heat or in the microwave. Allow to cool.
In a saucepan, combine the water and sugar and bring to a boil. Boil for 1 minute.
Using an electric mixture, beat the eggs in a large bowl until they are frothy. Slowly drizzle in the water/sugar mixture and beat at high speed for 5 minutes. The mixture will turn pale yellow and expand in volume.
With the mixer running, add the butter one piece at a time, beating well after each addition. At this point you might think you messed up, because the mixture will deflate and become "watery." Keep going until you've added all the butter.
Slowly add the cooled melted chocolate and beat at high speed for 5 minutes. Be sure the chocolate is cooled or you will end up with a sauce instead of an icing.