Make 2 different batter of same measurement.
In choco batter mix coco powder.
In white batter don't mix coco powder but make it with same measurement of ingredients .
Take a baking trey, grease it with butter .
Now pour 1 spn white batter in the centre of the trey.
Pour another spn of choco batter on the top of the white batter.
Don't shake it, it will spread by itself .
Keep on pouring both the batter alternatively until the batter is finish.
Micro it in high just for 2 mins.Your zebra cake is ready.