Overview: The second batch of bakers to whip up a storm are Evie, Billy, Shriyana and Nigel. Their baking knowledge and skills are put to the test when they are asked to follow Nadiya's surprise recipe for shortbread peanut butter squares. The shortbread squares need to be perfectly uniform in size with even layers, but which young baker will demonstrate the most precision to make it into the top two? Then they are asked to bake from the heart with a showstopper birthday cake for somebody they love. This bake brings out the best in the bakers as they have to think not just about the flavours and decoration their loved one would like, but also what could win them a place in the quarter-finals.