It's the biscuit-based quarter final, and Paul and Mary are taking the challenges to another level. To one of the most arduous ever seen on the Baking Show. The signature bake sees the bakers' organizational and baking skills put to the test, as they attempt to deliver a huge batch of perfectly baked crispbreads. The bakers then throw away the baking rulebook, as time and temperature work against them to produce six perfectly tempered chocolate tea cakes for the technical challenge. A place in the semifinal will be hard earned, as the final challenge tests not only the quality of the bake, but how well it works as a building material.