Vanilla sponge cake

Think I got this recipe from Zu and I agree with her, the sponge is so soft and light. This is a keeper.

I had an order again from my friend to make a simple sponge cake with jam. 

This is for the same lady that I made the mango mousse for. Yep, 1 year has gone by already and this time she asked for a bigger cake as she said the last time I made the cake, she nearly could not have any!
And as this was a last minute order, I could not make anything elaborate.

Ingredients:

(A)
150g cake flour/superfine flour
1/2 tsp (2g) baking powder
1/4 tsp (1g) salt
10g milk powder

(B)
60g cooking oil
50g water
4 (75g) yolks
80g castor sugar
1 tsp vanilla extract

(C)
4 (150g) whites
90g castor sugar (original 100g)
1/4 tsp (1g) cream of tartar

Method
1. Sift ingredients (A) and put it aside
2. Whisk yolks and sugar till it turns lemon colour
3. Add oil, water and vanilla and mix till well blended
4. Add ingredients (A) and mix it slowly till it forms a smooth batter
5. Whisk (C) till stiff
6. Fold in 1/3 of egg white mixture into egg yolk mixture and gently stir, then fold in the remaining egg white mixture and mix well gently

7. Pour batter into a lined 9" round cake tin
8. Bake in a preheated oven 180C for 35-40 mins or till it springs back when touched
9. Once cooked, remove from oven and invert the cake on the wire rack until completed cooled
10.Remove from mould and decorate it
* I cut the cake into 2 horizontally and added jam and then covered with butter cream.