Recipe for one 8" round tin
80g cake flour, sifted
66g vegetable oil or melted butter
32g castor sugar
4 egg yolks
2g baking powder
1 pinch of baking soda
1tsp vanilla paste (optional)
12g cocoa powder
60g hot water (for dissolving cocoa powder)
4 egg whites
62g castor sugar
1 pinch cream of tartar
1. Preheat oven to 180 degrees celsius
2. Dissolve the cocoa powder and baking soda together in the hot water.
3. Separate egg whites and egg yolks into 2 separate bowls.
4. Beat the egg yolks with sugar (32g) until sugar dissolves. Slowing mix in vegetable oil, and liquid cocoa mixture from Step 2.
5. Stir in flour mixture till even.
6. In separate mixing bowl (make sure it is greaseless and clean), whisk the egg whites till frothy, add in the pinch of cream of tartar and beat till almost soft peak.
7. Add in sugar (62g) in 3 batches and whisk till pale white with firm peaks.
8. Fold 1/3 of the egg white meringue into the egg yolk mixture. Then pour the lightened egg yolk mixture back into the remaining meringue and fold lightly till even. Be careful not to overfold.
9. Pour sponge cake batter into (ungreased) cake tin, smoothen the surface and lightly tap to release air bubbles.
10. Bake in the center shelf of oven (cake must be in center of oven) for 35-40 minutes.
* Try not to open the oven door during the first 30 minutes or cake will deflat.
If the top browns, quickly cover a piece of aluminium foil over it at 30 minutes and continue to bake.
11. Test doneness with a skewer, it should come out clean if cake is ready.
12. Remove sponge cake from oven and immediately invert of cooling rack to cool. Remove from tin only when cake is completely cool.