How to make
Beat the eggs with the sugar, add the oil, fresh milk, then sift in the flour with the baking powder and finally add the vanilla extract.
You can add lemon zest from one lemon if you wish, as well.
Set 5-6 spoons of the batter aside, and mix with the cocoa powder.
Pour the plain batter in a cake tin, and add the cocoa mix on top.
Stir slighly to create a marble effect and bake in a preheated oven at 360°F (180 degrees) for around 40 min.
Once the sponge cake has cooled down you can dust it with powdered sugar.
Enjoy!