Preheat oven to 160 degree Celcius. Line the pan with parchment paper. It is not necessary to grease the pan.

Sieve together cake flour and corn flour.

Place vegetable oil in a mixing bowl. Add yoghurt and mix to combine. Add egg yolks one at a time and mix to combine.

Add the flour mixture and mix until there are no lumps. Add vanilla extract and stir.

In a dry mixing bowl, beat egg whites with an electric mixer on low speed until mixture becomes frothy and foamy. Add half of the sugar and turn to medium-high speed and beat the mixture. Continue to add in the remaining sugar mixture in separate additions and beat until the egg whites reaches the soft peak stage.The soft peak stage is reached when the peaks of the whites curl over and droop slightly. Turn to low speed and beat for another 1 -2 mins (this helps to stabilise the air bubble)

Add the beaten egg whites to the yolk mixture in 3 separate additions, each time fold with a rubber spatula.

Pour batter into the prepared cake pan. Tap the pan lightly on a table top to get rid of any trapped air bubbles in the batter.

Place cake pan in a deep baking tray. Fill the baking tray with hot water (the water should rise up to about 1 inch of the cake pan).

Place on the lowest rack of the oven and bake at 160 degC for 60 mins.

Remove cake pan from oven and immediately drop the pan at a height of 20~30cm onto the table top. This helps to prevent the cake from shrinking upon cooling. Unmould the cake immediately. To unmold, place a large plate or baking sheet on top of the cake pan, invert the cake pan onto the plate/baking sheet. Remove the cake pan and the parchment paper on the base and sides of the cake (Note: do use oven mitten as the cake pan will be very hot). Chill for 2-3 hours or overnight in the fridge.