This recipe appeared on this blog back in June 2007, but I've adjusted the quantities and method a bit over the years, and I'm sure the resulting biscuits are better now. I made some yesterday to take to work today ...
200 g (7 oz) butter
50 g (2 oz) sugar
175 g (6 oz) flour
25 g (1 oz) cocoa powder
75 g (3 oz) crushed cornflakes (or crushed Weet-bix)
Soften butter. Add sugar and beat to a cream. Add flour and cocoa. Lastly, mix cornflakes in. Put spoonfuls on a greased oven tray and bake about 15 minutes at 180 degrees C (350 degrees F). When cold, ice with chocolate icing and put walnuts or pecans on top.