I made the Chocolate Malteser Cake but it had a very liquid batter and the sponges were thin. Would a 7-inch sandwich tin be better?
Nigella's Chocolate Malteser Cake (from FEAST) is a chocolate malt flavoured cake. It is slightly unusual as it has a low amount of fat and the method is similar to a genoise sponge as the eggs and sugar are whisked together before the other ingredients are added. The batter is quite liquid, but this helps to give a moist sponge.
The sponges should rise fairly well as they contain both baking powder and bicarbonate of soda (baking soda) and make sure that both of those are in date. Also make sure that the oven is turned on and properly preheated by the time the batter is mixed, as if it stands for too long after mixing then the sponges may not rise as much. Whisking the eggs and sugar helps to add some air, so you need to make sure that they are whisked to "ribbon" stage - when you lift the whisk the mixture should fall from the whisk in a thick ribbon and leave a trail on the surface of the mixture in the bowl for a couple of seconds.