My Nan used to make these for us when Zeltus and I were children, to her it was recycling those old wasted biscuits and crumbs that collected in the bottom of the biscuit barrel but to us it was magic how it turned from a mess into something solid and wonderfully tasty.
225g Rich Tea Biscuits or broken plain biscuits for varied taste/texture
115g Salted Butter
3 rounded tablespoons of cocoa powder - I use Green and Black's organic cocoa
55g of caster sugar
2 heaped tablespoons Golden Syrup (well big dollops of the golden stuff cos I cannot get a heaped tablespoon to save my life)
115g plain chocolate although I used milk because of the cocoa content...for a richer taste. NB Don't use cooking chocolate though.. won't be as good.
Roughly crush biscuits in plastic bag with rolling pin
Melt butter and add caster sugar, cocoa powder and Golden Syrup
Melt chocolate and add to mixture with crushed biscuits
Spoon mixture into a sheet of greaseproof paper, roll into a sausage and leave in fridge to harden
For extra zing, my Nan used to roll her cake in grated chocolate or cocoa powder. Personally I leave it plain as it looks good when sliced and eaten and surely that is what counts most.