
Add all the ingredients except the walnuts to a food processor and blend. Don't blend too long because you don't want a paste! You might need to scrape down the sides once of twice.
When you are happy with the consistency, add the walnuts and blend for a second or two more. Adding the walnuts in at the end is totally optional, I just prefer the bit of crunch they add to the balls!
Roll into balls and put in the freezer for 15 minutes.
In the meantime melt the chocolate over a double boiler.
Dip the balls in the chocolate and roll in some more desiccated coconut if desired. Store in the fridge for up to three days, otherwise keep in the freezer.