Japanese dark pearl cake

This is my second weekend where I get to bake early in the morning, and managed to get everything done and clean up within an hour or so.  Although I lose so sleeping time, we are able to carrying on with our day's activities more leisurely. Like last week, we went for a swim today and since it's still early the pool is pretty empty and water seems cleaner. We'll see how long our new swimming sessions will last.

Japanese dark pearl cake
(Recipe adapted from aunty yochana)
Original recipe is for 23-25 inch tube pan, I halved the recipe for my 21 cm tube pan

Ingredients/ Method:
Cocoa Batter:
75g chocolate, chopped
45ml water
50g corn oil
12.5g cocoa powder
32.5g cake flour
1/4 tsp bicarbonate of soda
57.5g egg yolks (about 3.5 eggs)

Egg White Batter:
112.5g egg white (about 3.5 eggs)
45g castor sugar
a pinch of salt
1/16 tsp of cream of tartar

1) Melt chocolate in microwave for 2 mins on medium and stir till smooth. Add in cornoil and stir till smooth. Fold in the rest of the cocoa ingredients and stir till smooth. Set aside.
2) Whisk egg white with cream of tartar till frothy, then pour in sugar gradually and then add in the salt. Whisk till a medium peak.
3) Add about 2 cups of egg white to the cocoa batter and mix well.
4)  Fold cocoa batter into the remaining egg white evenly.
5) Pour into 21cm tube pan and bake in pre-heated oven at 170 deg C for 45 mins.
6) When done, remove the tube pan from the oven and invert on a cooling rack and leave to stand for 2 hours.

Update 25 May 2012: I had the cake on Monday & Tuesday as breakfast, and it's soft, spongy, moist & chocolatey! Nice <3