Prepare a 9-inch baking pan, using oil and parchment paper.
Separate the egg white and egg yolks.
In a big bowl, add the egg whites and start beating at high-speed using an electric mixer.
After 2 minutes of beating the eggs, add the sugar little by little and keep beating until all the sugar is added and dissolved in the egg whites. Egg whites and sugar mixture is ready when it is 3 times in volume, glossy and pure white in color and is very thick. It would take around 6-8 minutes to reach this consistency and texture.
Add one yolk at a time and keep beating at high speed until all the yolks are well mixed.
Beat for another 4-5 minutes.
In another bowl, mix plain flour and cocoa powder.
SIFT half of this mixture into the egg whites mixture.
Now mix it using a hand whisk gently so that mixture remains frothy and airy. (please watch the video for the mixing technique).
Add the remaining flour and cocoa mix and repeat until the batter is well combined.
Bake in the oven at 150°C using only the lower rod for 30-35 minutes until the toothpick inserted comes out clean.
Take out and leave the cake on the countertop.
Let it come to room temperature before removing from the pan.
