Sift together the flour and baking powder.
Separate the yolks and egg white.
Whisk the eggs till soft peaks are formed.
Powder the sugar and whisk together with the butter.
Add into this the egg yolks and whisk till well incorporated.
Add the flour and beat till combined.
Slowly add the milk, pulp and vanilla essence and whisk.
Gently fold in the egg whites.
The batter formed should be pouring consistency, like a pancake batter.
Pour into a greased dish and bake at 180 deg for about 45 minutes.
The top will be browned and the insides still a little mushy.
Cover with a foil and bake for a further 10 minutes or so.
Check the centre with a skewer before removing from the oven.
If still mushy, bake 5 minutes more, under cover.
Remove onto a rack.
Dust with castor sugar while still warm.
The ready cake would be in three layers – the top crisp, the sponge middle and the custard base.