Chop the nuts into small pieces and mix with the coconut.
Melt the chocolate in bowl resting on top of a pan of simmering. Mix in the butter or margarin. Stir until the butter is completely melted.
Take the bowl off the pan. Add the walnut-coconut mixture to the melted chocolate and mix well.
Refrigerate for 10 minutes.
When it’s slightly hardened, drop spoonfuls of the mixture onto a sheet or plate lined with baking paper. Chill until they firm up.
Dust them with some icing sugar just before serving.