banana chocolate chiffon cake

Ingredients [A]
> 4 egg yolks
> 50g corn oil
> 25g milk
> 80g bananas (mashed)
> 80g Cake Flour (sieved)

Ingredients [B] 
> 4 egg whites
> 70g castor sugar

Ingredient [C] 
1 tbsp cocoa powder and 1 tbsp hot water, mixed, to be used later.

Method
[1]  Sieve cake flour and set aside.
[2]  Mix Ingredients [A] - beat egg yolk and corn oil, pour in milk, mix in mashed banana.
[3]  Lastly add in cake flour and mix with a mixer.
[4]  Beat Ingredients [B] till stiff.[5]  Remove one third of the white batter to mix into the yolk batter, fold.
[6]  Mix in the rest of the white batter and fold.
[7]  Take half of the mixed batter and add in cocoa mix.
[8]  Pour banana batter in an 18" chiffon mould.  Tap pan lightly to get rid of trapped air bubbles.
[9]  Add in cocoa batter, with a chopstick or knife, move around the batter in circles. 
[10]  After preheating oven, bake at 170°C for approximately 30-35 minutes.
[11]  Invert the pan immediately and let it cool completely before serving.