The Bake Off returns and for the first time ever, the tent welcomes a baker's dozen to do battle. Mel Giedroyc and Sue Perkins coax them through their baking trials, all the while under the scrutiny of the inimitable judges Mary Berry and Paul Hollywood. With a range of baking styles and personalities, the Bake Off tent is packed with the best amateur bakers from around the country; from space engineer to student, teacher to dentist, psychologist to carpenter. But after ten weeks of whisking, crimping and piping, only one can emerge victorious. This time, nobody is safe because Mary and Paul may decide to lose not one but two bakers at any time.The judges set the signature challenges as true home baker staples so that they can immediately see the bakers' personalities and their range of skills and ideas, setting them apart from each other. The first challenge is a sandwich cake. While this might seem simple, there is a difficult choice to be made between going for the classic or being experimental. Something tried and tested might not stand out, but going for ambitious flavours and ideas could miss the mark.Mary's first technical challenge is for angel food cake, which is not the bakers' idea of heaven as they attempt to follow the bare bones of the recipe, which proves to be a recipe for disaster for some. The showstopper explores all things chocolate, and is their final chance to secure their place in the Bake Off and save them from being the first to leave the tent.