Overview: Nadiya and Allegra have already chosen their first five quarter-finalists and only five places remain. The four bakers out to impress in the tent are Jenna, Ali, Dylan and Robin, who are tasked with following the recipe for a chocolate ginger volcano biscuit. The trick is to use bicarbonate of soda to create an explosive honeycomb centre. Next they tackle a food illusion showstopper, creating sweet bakes made to look like a savoury meal. Who will perform the magic to conjure a place in the quarter-finals?