How to cook
Crumble the biscuits. Beat 2 packets of butter, 1 cup powdered sugar and the vanilla, mix in the biscuits, chopped walnuts, egg and cognac. Knead a dough.
Shape small rocks from the dough. Combine the cocoa and sugar for the glaze and put them in a little water to melt them. Stir to get a uniform mixture.
Before the mixture boils, pull it from the fire, add the butter and stir to dissolve it. Coat the small rocks with the chocolate glaze. Put them in the fridge to harden.
Optionally, you can decorate them with white chocolate.