In large sized bowl, mix all purpose flour, soda powder and vanilla essence.
In another bowl, add sugar powder, butter and little hot water. whisk well till it is combined.
Now mix the flour mixture into the sugar mixture. Whisk and combine again.4) Add the water in between slowly and mix again.
When it becomes a soft batter, take ¼ part and pour it in small bowl.6) Add the coco powder into it and mix well.7) In the baking tray, apply the butter in sides and pour the white cake mixture in one side and on the other side pour the coco mixture.