It is week two of The Great British Bake Off, and it is crunchtime as Paul and Mary set the bakers three biscuitchallenges.The bakers start with a signature challenge, butwho will snap first with just a few hours to make 24 identicaldecorated biscuits?Hidden under the gingham cloth is atechnical challenge that requires perfect piping to avoid acrumbling whirl.Sue Perkins drops in for tea and history as shediscovers the etiquette of dunking biscuits, from Victorianhigh society right back to Greek survival biscuits.The finalshowstopper challenge requires precision baking to build abiscuit structure that reveals a little more about each of thebakers.