Can I Make A Rectangular Lemon Polenta Cake?

Our answer

Nigella's Lemon Polenta Cake (from KITCHEN) is a gluten-free cake made with ground almonds and fine polenta. The cake is soaked with a lemon syrup after baking. The recipe uses a 23cm/9-inch round springform pan. These pans tend to be quite deep — usually at least 3 inches deep.

For a rectangular pan it will depend partly on how deep the pan is. We are assuming that the cake pan is 9 x 13 x 2 inches, which is a fairly standard US pan size. For this size of pan we suspect that you will need to increase the recipe quantities by 25-30%, which would need 4 eggs. The baking time is slightly tricky but many traybakes of this size take around 40 minutes to bake, so we would suggest that you start checking the cake at around 30 minutes and then checking every 5 minutes after that until the edges of the cake have set and are coming away slightly from the sides of the pan and a cake tester inserted into the centre comes out clean or with a few damp crumbs attached. However, we would caution that as the cake is gluten free, it does tend to sink a bit in the centre. With a larger cake in a rectangular pan this could be more pronounced and noticeable, so it may not be an ideal cake to make in traybake form.