Bolu Kukus (Steamed Sponge Cake)

Bolu Kukus / Steamed Sponge Cake is one of the famous cakes/"jajan pasar" from Indonesia. You can find it mainly from "pasar" (traditional market) and bakeries with many colours and flavours: chocolate, strawbery, pandan, vanilla.
The texture of this cake is soft, like Western muffins, but the top is the unique look.


It looks easy to make Bolu Kukus but you have to know the techniques used to make it fluffy and the top can open up.
The use of baking soda is important or you can substitute with carbonated water.

From the name itself, we know that steaming is the method to make this cake. First of all, you need to use special mould with many holes (it looks like cupcake mould, which I haven't found this kind of mould sold here in Perth. I have to get it from Indonesia). This mould will allow the steam from the bottom to enter into the dough so that the cake will cook evenly. It looks like this picture below


My first try making Bolu Kukus was unsuccessful. The top didn't open up & my techniques were wrong.
Since the result is kind of cute, I upload the unsuccessful ones for comparison.