Mix flour and baking powder well

Separate egg yolks from egg whites. Beat the egg white with an electric beater till stiff peaks appear.

Mix the egg yolk,sugar and oil in a grinder. Add the beaten egg whites to this mixture. Also add vanilla essence.

Slowly ,2 to 3 tablespoons at a time, add the flour to the wet mixture.

Add the vinegar to milk and let it stand for sometime..now add this milk to the cake batter.

Divide the batter into two parts. Add cocoa to one part.

Pour the part without cocoa in the cake tin. Layer the cocoa part on top of it.

Now move a fork in the batter so as to slightly mix it

Bake at 160 C for 45 to 50 mins