How to make
It is easiest to use a blender or food chopper - blend the biscuits and combine them with the walnuts, sugar, butter, cocoa and rum.
Shape the mixture into identical rocks by hand. Arrange them on a paper towel.
Melt the chocolate in a water bath and add 1 tablespoon of butter. Pour the glaze over each small rock using a tablespoon.
Put the small rocks in the refrigerator. After the glaze hardens, sprinkle with coconut flakes if desired.