I made the Honey Chocolate Cake and it overflowed out of the tin in the oven, then after an hour I was left with a completely sunken mess. What happened?
Nigella's Honey Chocolate Cake (from FEAST) has quite a liquid batter and the only raising agent used is 1 teaspoon of bicarbonate of soda (baking soda). It should therefore not actually rise up too much and have a moist, close crumb. From the description of the cake we suspect that too much raising agent could have been used, causing the cake batter to bubble up in the oven and overflow, and then sink back dramatically on cooling. If you taste the cake it may taste slightly bitter or soapy and this would usually indicate that too much bicarb has been used.
It should be only 1 (5 ml) level teaspoon of bicarbonate of soda and the flour should be plain flour and not self-raising, as this already contains raising agents. We would also mention that the tin should be a deep springform tin and not a shallow sandwich tin. If the cake batter comes more than halfway up the sides of the tin then there is always a risk that the cake batter could overflow out of the tin.