Rocky Road Crunch Bars

Our answer

Nigella's Rocky Road Crunch Bars (from NIGELLA EXPRESS here and on Nigella.com here) are a no-bake bar made from melted chocolate and butter with mini marshmallows and crushed biscuits (cookies). The mixture is put into a 23cm (9-inch) square tin, which has the same capacity as a 25cm (10-inch) round tin. So if you put the mixture into a 20cm (8-inch) round tin it will be a slightly deeper cake, which may suit your needs. We would suggest using a springform tin that has the base lined with baking parchment, for easier removal. This type of bar can be difficult to cut if it is too deep or too cold, but a heavy sharp knife or a serrated knife may be helpful.

It is not an ideal vehicle for rolled fondant icing as this Rocky Road should be kept in the fridge, and unfortunately refrigeration can cause some fondant icings to "sweat" and turn sticky. However if you do want to follow this route then you would need to make a smooth surface by spreading a layer of ganache over the top and the sides of the cake. Ganache is a mixture of equal weights of melted chocolate and double (whipping or heavy) cream. Let the ganache set fully before adding the fondant icing.