Heavy Sponge Cakes
Q: I tried making your sponge cake and it wasn't fluffy and light! It came out of the oven quite heavy. My egg mixture was lovely and light before adding the flour and cornflour so why did this happen? - Effie
A: The main reason that may have caused your sponge to be heavy (and not fluffy and light) is that the batter could have been over mixed once the flour and cornflour was added. This would not only develop the gluten in the flour, ultimately making the cake crumb tough, but also would mean that a lot of the incorporated air would have been lost in the process hence making the cake less light and more dense. It is important that the flour and cornflour are gently and briefly, but thoroughly, incorporated – either by folding in or, in the case of this particular recipe, by whisking gently and briefly. It can be a little tricky to get the right balance with this technique but it does get easier with practise.
The other thing to check is that you used self-raising flour in this recipe. Some very traditional sponge recipes use plain flour without a raising agent, but this particular recipe uses self-raising flour to help give it extra lightness and lift.
Another possible reason is if the cake was over-baked. This generally causes a sponge to become dry but this can then lead to it being dense and heavy. If you baked it for the recommended time it may mean that your oven is running hot and that the baking time needs to be shortened slightly next time you make it.