Preheat the oven to 180° C. Prepare a baking pan.
Apply butter on all sides.
Mix the flour and baking powder in a bowl.
In a mixing bowl beat together egg white ,sugar and vanilla essence.Add in milk,salt,oil and mix well.
Take half of the batter in to another bowl and mix in cocoa.
Now take the baking pan and pour 2 tblspn of white batter,next in with cocoa batter and repeat this step till the batter is finished.
Bake it in the oven for 45-50 min or until the cake is cooked.To check whether the cake is cooked,Insert a skewer in,if the skewer comes out clean then the cake is done.
Let the cake cool completely before removing it from the tin and slice it into wedge and serve.
