Week seven of The Great British Bake Off is Dessert week. Three sweet challenges which will mean a bitter end for one of the six remaining bakers as they battle for a place in the quarter-final.For starters the bakers face a sweetly filled signature challenge that has them rolling out their skills to impress Mary and Paul.And if that wasn't enough, the technical challenge is one of the toughest of the series so far, which layers on the pressure as the bakers are tested on a tricky French dessert.Sue heads to Paris for a lesson on the history of praline and nibbles on a few of these nutty delicacies.And finally there is a multi-bake mini-showstopper that is a bit of a mousse marathon. But which of the bakers will impress Mary and Paul enough to earn their place in the quarter-final, and which baker will be hanging up their apron and heading home?