Here's the recipe which I have adapted from The Kuali:-
140g castor sugar (original is 175g)
4 eggs, separated
1 cup well mashed very ripe bananas (add 1 tsp lemon juice to mash)
235g self-raising flour, sifted (I used top flour with 1 tsp baking powder)
3/4 tsp baking soda
1.5 tablespoon lemon juice
1 tsp grated lemon zest (I obmit this)
Grease and flour a 21cm cake tin and preheat oven at 170 degC. Obviously, I made them into cupcakes instead.
Beat sugar and butter till light and creamy. Add egg yolks one at a time and beat well.
Add mash bananas and fold in sifted flour/baking powder/baking soda, lemon juice and zest, if using.
Beat egg white till stiff and gently fold into banana mixture.
Pour batter into prepared tin or cupcakes moulds (paper lined) and bake for 45-55 minutes if you are using the cake tin or 25 minutes if making into cupcakes. The chocolate chips are optional. Scatter on the top of the cake before baking.