Why Is My Lemon Polenta Cake Sinking In The Centre?

Our answer

Nigella's Lemon Polenta Cake (from KITCHEN) is a gluten-free cake made with polenta and ground almonds. As the cake is gluten free it will tend to sink slightly on cooling (you may be able to see this from the photo). Flour contains gluten, which hardens as the cake bakes and this structure holds up once the cake has cooled. Without the gluten, the cake will sink slightly as the warm air trapped in the cake cools and contracts.

We are slightly concerned to hear that that the cake is rising excessively in the oven, as this will lead it to sink back more as it cools. The excessive rise can be due to a few things. First, make sure that you measure the baking powder using a set of proper measuring spoons and use level spoon measures and don't use too much. Second, don't beat the fat and sugar too much, as too much air whipped into the mixture can also cause it to rise excessively in the oven. You want the ingredients to be combined and for the sugar to start dissolving. Finally, if the oven is too hot then it can cause the outside of the cake to bake too quickly, pushing the centre up but then causing it to collapse. So you may want to check the oven temperature and bake the cake on the middle shelf.