1Pre heat the oven at 140 degree C. Grease and dust a 11 "x 7 1/2 " rectangle baking tin.Sift the flour and baking powder thrice. Keep it aside. Powder the sugar .
2Separate egg whites and egg yolks.
3 Beat the egg whites until stiff by adding 1/4 of the powdered sugar.
4In another bowl ,beat the egg yolks for a minute .Add 1/4 cup of water and rest of the powdered sugar .
5Continue beating until it is almost stiff and pale yellow in colour. Add vanilla essence .
6Gently fold in flour.Do not stir the batter.
7Now gently fold in beaten egg whites.
9Transfer it into the prepared cake tin . Give the tin a gentle tap .
10Bake for 14-15 mins or until done.