Grease and flour a 23cm round cake tin. Preheat oven to 180°C. Place eggs and sugar in a mixing bowl over a large pan of simmering water and whisk briskly until mixture thickens and almost doubles in volume.

Remove bowl from the simmering water and continue to whisk until mixture turns cool. Mix in sifted flour. Gradually drizzle in the cooled melted butter and pandan essence. Fold in gently with a metal spoon.

Pour mixture into prepared tin. (Smoothen the surface with a spatula.) Bake in preheated oven for 25 to 30 minutes or until cooked. The cake is cooked if the surface is golden brown and it shrinks slightly from the sides of the tin.

Remove cake from oven and leave to cool in the tin for 5 to 6 minutes before turning out on a wire rack.