Preheat oven to 180 degrees C. Line a baking sheet with baking paper. Mix flour and cocoa powder. In large bowl, cream butter and sugar. Add the flour cocoa mixture to butter mixture with spoon. Fold in cornflakes.
Make balls about 2 teaspoons in size. Put on baking sheet and flatten slightly. Bake for 10-15 minutes then allow to cool on wire rack.
To make icing: Mix icing sugar, water, cocoa and butter until smooth. Spoon onto cooled biscuits and top with a walnut half.
Well I don't want to give myself a bad review here, but I really am not happy with the icing on these (It could be the brand of coco I used). I will post another recipe with better icing soon. AFTER I give it a go first. The the biscuit was great! - 12 May 2012