This plain sponge is always popular, particularly if filled with passionfruit cream or vanilla cream and berries.
Sift the custard powder, cornflour, bi-carb soda and cream of tartar. Set aside.
Divide the batter between the two prepared tins.
When cool, split each sponge in half and fill with whipped cream which is lightly sweetened with a little sugar, and flavoured with vanilla. You could ice the sponges, if you wish, but we prefer just to dust them with icing sugar.