Judges Nadiya and Allegra set bakers a technical recipe for a British classic battenberg, with a bit of a twist. This rhubarb and custard version tests the bakers' precision skills as they must make four identical sponges and construct them into the perfect checkerboard.

Harvey, Joseph, Macy and Sophie produce a show-stopping selfie on a giant cookie. How will they portray themselves in icing and how evenly baked will their whopping 30cm cookie turn out? It's for one of the last two places in the quarter-finals so Nadiya and Allegra are looking for perfection. Show less