Chocolate Chiffon Cake

Ingredients:

(A)
4 egg yolks
135ml water
85ml vegetable oil
1/4 tsp salt
100 g sugar
135 g flour
15g cocoa powder
1 tsp baking powder

(B)
4 egg whites
90g sugar
1/8 tsp cream of tartar

Method:

1. Preheat oven to 170 degC
2. Sieve together flour, cocoa powder and baking powder and set aside
   
3. Whisk egg yolks and sugar in a mixing bowl until sugar just dissolved. Add in salt, oil and water. Whisk till combined. Sieve over the flour mixture and fold gently with a spatula until flour is fully incorporated into the batter.
4. In a clean, dry mixing bowl, whisk egg whites and cream of tartar with an electric mixer until mixture becomes frothy and foamy. Add in the sugar in 3 separate additions while beating at high speed till stiff peaks form.
5. Add the egg white foam into the egg yolk batter in 3 separate additions, each time folding gently with a spatula until just blended.
6. Pour batter into a 22cm round pan (do not grease the pan). Spread and smooth the batter evenly with a spatula. Bang the pan gently on a work surface several times or cut thru the cake with a spatula to release the air bubbles trapped in the batter.
7. Bake for 25 ~ 30mins or until the cake surface turns golden brown, and a skewer inserted into the centre comes out clean.
8. Remove from the oven and invert the pan immediately. Let cool completely before unmould.