Melt the butter or the margarine and remove from heat.

Then add the icing sugar, the cocoa powder and the brandy and mix all the ingredients well.

Add the biscuits, crumbled, as well as the walnuts and mix well.

Set the mixture aside to cool and when it sets spread it on the aluminum foil or any other kind of greaseproof paper and wrap it into a roll. 

Place it in the freezer to freeze.

When it freezes, sprinkle the top with finely ground biscuits.

Cut into slices and serve.