Double Chocolate Butter Sponge cake

Most sponge cakes use oil but I always prefer butter; anything with butter tastes better! Anything with cocoa also tastes better and with added melted chocolate, what more can I say?

Ingredients:

6 yolks (+- 65g egg with shell)
80g butter
100g milk
90g cake flour (sift with cocoa, soda n salt)
15g cocoa
Small pinch of soda bicarbonate 
1/4 tsp salt 
50g cooking chocolate (melted)

6 whites
105g castor sugar
1/4 tsp cream of tartar 

8″ round pan or 7” square pan

Method
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1) Preheat oven to 170 degrees with water bath.

2) Line bottom of pan and grease the sides.

3) Melt butter in microwave for 40 seconds with the milk.

4) Pour hot butter/milk into sifted flour/cocoa mixture

5) Mix with spatula and add yolks and followed by melted chocolate.  Set aside.

6) Beat the whites till foamy before adding cream of tartar and then pour in sugar in a slow stream.  Beat till firm peaks. The firmer your meringue, the higher chance the cake will crack!

7) Fold meringue into yolk batter in 3 batches till well incorporated.  

8) Slowly pour batter into pan tapping the sides of the bowl to release bubbles.

9) Bake at 160deg for 100mins top n bottom heat on the lowest rack. At end of 100mins, remove water bath and bake for another 5 mins.

10) When cake is done, off oven and wait for 10-15m for the cake to pull away from the sides. Check for parts which are still stuck and gently dislodge with spatula. 

11) Unmould and put cake back into oven to dry in oven’s residue heat.