Fluffy Chocolate Sponge Cake

Ingredients:
10g cocoa powder
25g corn oil ~ hot
10g fresh milk ~ cold
1/8 tsp salt
1/2 tsp vanilla extract
10g glucose
2 whole eggs + 1 egg yolk
80g caster sugar
50g cake flour
1/8 tsp baking soda

Directions:

1. Preheat oven to 170 deg C.  Grease cake pan with butter & line pan with parchment paper.
2. Heat oil till very hot (almost smoking).  Add into cocoa powder & mix thoroughly.  Let mixture cool down slightly (bowl doesn't feel hot but quite warm), then add milk & stir thoroughly.  Add vanilla & salt, stir well & set aside to cool down completely.
3. Whisk glucose, eggs & yolk till starting to thicken.  Gradually add castor sugar whilst still whisking.  Continue whisk till mixture is thick & pals, reducing speed towards the end to remove big air bubbles.
4. Add cocoa paste in 2 batches.  Whisk till you don't see any streaks of cocoa after each addition.  Scrape bottom of bowl with spatula & fold till evenly mixed.
5. Sift cake flour & baking soda into bowl in 2 batches.  Mix with whisk after each addition, stirring just top part of egg mixture.  Scrape down & fold with spatula till just mixed.  Banging mixing bowl against worktop 2-3 times.
6. Pour batter into cake pan.  Tap pan against worktop 2-3 times.
7. Bake on bottom rack of the oven till batter doesn't move when gently jiggled for about 20 mins.  Rotating pan as necessary so that cake rises evenly.  Transfer to middle of oven & continue baking till skewer inserted into center of cake comes out clean, another 5 mins.
8. Remove cake to wire rack.  Wait a few moments when top of cake starts to wrinkle, then unmould.  Peel paper from sides of cake.   Leave cake on wire rack to cool down.