Hi Team Nigella! If I want to make a smaller sponge cake and reduce the ingredients by half from your buttermilk sponge cake recipe, will the cooking time be the same or will it be half the time? For example if I use 125g instead of 250g of flour, and reduce the other cake ingredients by half, will the cooking time at 180c be half of that in the recipe?
Nigella's Buttermilk Birthday Cake (from HOW TO BE A DOMESTIC GODDESS) can be baked as one large cake, or as two layers of a sandwich cake. However scaling down cakes is not straightforward and the baking time is likely to be slightly longer than half of the time in the recipe. It would also depend on the size of the pan used. So unfortunately it is difficult for us to advise on scaling down of the cake.
If you want to make a half quantity of a sponge cake mixture then it is easier to make cupcakes instead. A half quantity of the Buttermilk Birthday Cake should make about 12 cupcakes, if you fill the cupcake cases half to two-thirds full with batter. They should take about 20 minutes to bake at 180c (350F), but start checking at about 18 minutes. A toothpick inserted into the centre of one of the cupcakes in the middle of the pan should come out clean. You may also like to try Nigella's Cupcakes recipe as an alternative.