Grease a baking pan with butter and dust it with flour, keep it aside.

Shift the flour along with baking powder, and salt in a big bowl, keep aside.

Separate the egg whites and take the egg whites in a bowl. Beat well till it is foamy and forms peaks. Add the Vanilla essence and gently mix in.

Get the butter to room temperature and beat well using a spatula until it turns really soft.

Then add the icing sugar and continue beating it. Do this till you see the butter turning soft.

At this stage add half of the egg whites. Combine everything well slowly.

Add the shifted flour and gently fold it in one direction. Gently fold in the rest of the egg white mixture. Finally add the remaining flour. Gently fold everything together.

Preheat the oven at 185 degree C.

Pour the batter into the prepared cake tin.

Bake at 185 Degree C / 365 degrees F for about 30 minutes till cake springs back when touched lightly in the center.

Invert the pan and let it cool. Remove the cake from the pan once it is cooled.

Slice it into small pieces

Serve warm.