Line the bottom and sides of an 8 - inch tin with parchment paper. (baketheneat.com)
As the cake was only for my husband and I, I halved the ingredients to make a smaller cake, using an 8 inch tin rather than the 9 inch specified and that was right for the amount of mixture. (madebyjayne.com)
I'm not sure off hand how much batter you'd need but probably a double batch for 24 cupcakes worth of sponge would be enough to fill two 9 inch tins. (maisoncupcake.com)