Why Is My Old Fashioned Chocolate Cake So Flat?

Our answer

Nigella's Old Fashioned Chocolate Cake (from FEAST) has moist and tender sponge layers that benefit from the addition of sour cream. The cake batter itself is exceptionally easy as all of the ingredients are mixed together quickly in a food processor.

There are a few reasons why the sponge may appear flat. The cake pans should have a diameter of 20cm/8 inches. If they are larger than this then the sponge layers will seem flatter, so it may be worth checking the size of your pans. The leavening is a combination of baking powder and bicarbonate of soda (baking soda) with plain (all-purpose) flour. If you are using a cake or sponge flour then check the packaging as it may already contain leavening and you will need to use plain flour instead. Make sure that your baking powder and bicarbonate of soda are both within the "best before" date as they become less effective over time. Also measure the quantities carefully with 5ml/1 teaspoon and 2.5ml/½ teaspoon measuring spoons and don't get the baking powder and bicarbonate of soda the wrong way around. Too much leavening, or the wrong combination, can make the sponges rise up a lot in the oven but then they completely collapse back as they cool. Finally, bicarbonate of soda acts very quickly and this means that the cake batter needs to go into the oven as soon as it has been made. Make sure that your oven is properly heated and your pans are greased and lined before you make the cake batter. Only process the ingredients enough to mix them into a homogenous batter, then transfer the batter to the pans and put into the oven straight away to bake.