Baked 'giraffe' egg cake (烤鸡蛋糕)

I've recently joined a new group 手工烘焙♥ 甜品饮料 on Facebook and oh my, it's so active and there are many sharing of recipes. Baked egg egg  (烤鸡蛋糕) seems to be a very popular recipe for quite a while, and I finally managed to try my hand on it. My idea was to make a giraffe-patterned cake, but it seems a failure as my boy asked "where's the giraffe? where's the giraffe head? hahaha...

I've referred to Anncoo blog who has the recipe in English, and copied here for ready reference. Overall the cake is really soft & fluffy, and taste like the old-time 鸡蛋糕, but my boy doesn't fancy it.

Ingredients:
3 egg whites
65g icing sugar
3 egg yolks
1 whole egg
50g corn oil
65g self-raising flour
5g cocoa powder + 1 tbsp hot water

      Method:

• In a mixing bowl, mix egg yolks and whole egg together with a hand whisk. Add in corn oil till combined. (I've used the mixer instead.)
• Sieve in self raising flour and mix well, set aside.
• Whisk the egg whites to bubbly at medium speed and add icing sugar into it in 3 batches and whisk to stiff peak.
• Add one third of meringue to egg yolk mixture and fold well with a rubber spatula. Then pour all the egg mixture into the meringue at low speed and mix well. 
• Pour mixture into a 5 x 8 inch lined cake pan (or a 6 inch square cake pan), leaving 2 tablespoon of plain mixture and mix with the cocoa paste. Drop dollops of mixture on the top of cake. (I didn't lined or greased the pan at all.) 
• Bake in preheated oven at 170C for 35 minutes.
• Overturn the cake immediately once cake is out of the oven. Leave to cool before cutting into slices.