Never Fail Sponge Cake
4 eggs, separated
3/4 cup caster sugar
1 tbspn custard powder
3/4 cup cornflour
1/2 tspn baking soda
1 tspn cream of tartar
Turn oven on to preheat at 165c and grease around baking tin.
Beat egg whites until stiff. Continue beating while gradually adding sugar.
Add egg yolks, beat until well combined.
Add triple sifted (from a height) dry ingredients to egg mix and fold using a slotted metal spoon.
Bake for 25 minutes (the original recipe said 20 but mine wasn't quite ready at that time, so consider your oven's pernickety temperament when setting a time).
Leave in the tin for 5 minutes, then remove and place on a rack to cool.