Hi, I want to make Nigella's Custard Sponge Cake (from Feast) for my Mum's Birthday this Saturday and the recipe states that two 20cm cake tins will be required. I have measured my cake tins and they measure 20cm across the top from lip to lip but only 17cm on the bottom and therefore on the inside. Is this the right size tin or is this considered a 17cm cake tin? If I do use these will I have too much mixture to fit in? HELP!
Normally a cake tin is measured from inside edge to inside edge, so the measurement does not include any lip, nor dies it include the thickness of the edges of the tin. It is therefore likely that your tin is a 17cm/7-inch one and not a 20cm/8-inch one.
When you put the cake batter into a tin it should not come more than halfway up the sides of the tin. If you don't want to buy new tins then you could make up the cake batter from the recipe but as well as prepating your round cake tins you should also pop a few paper muffin cases into a muffin tin. Put enough batter into the tins to come halfway up the sides then use the remainder of the batter to make a few cupcakes. The cupcakes can bake at the same temperature as the cakes but are likely to take around 12-15 minutes. It may be worth baking the cupcakes separately as if you open the oven before the larger cakes are cooked then the larger cakes could sink slightly.
Make some extra buttercream filling to frost the cupcakes with as cupcakes usually require proportionally more frosting than large cakes.