I read that baking soda can act as a leavening agent with mixed with fruit juice, yogurt and vinegar. So, I went along experimenting.
On my second attempt, I tried mixing with mixing with yogurt. The result was a failure, probably due to a heavy batter (125g mashed pumpkin, 2/3 cup of shredded carrot , 1/3 cup of chopped walnut and 1/2 cup yogurt) and only 1/4 tsp of baking soda. The cake didn't raised and was more looked more like kueh. I have to steam it for 45 min for it to be fully cooked.
|the cake wouldn't raise|
|looks more like kueh|
Not wanting to give up, I tried again with a lighter batter. And it was a success! This time I used 1 small banana, some walnut and 1/4 cup of yogurt. I opt not to use sugar as I thought banana should be quite a sweet substitute.When I saw the mini cakes rise, I was over the moon! So, I am on the right track. The resulting cake is not sweet and it got me really excited to experiment more, what about increasing the amount of banana?
So the next experiment was a few days later, I promised to make my mom some. This time, I ran out of yogurt, I substitute with 1 teaspoon of vinegar. Hmm... I really wonder whether it would affect the taste of the cake but I guess a little won't hurt. This time, I grind some cashew nut into it. My mom can't take nuts as her gums are weak. I added also blueberries to make it even sweeter. The result cake, I find is rather sweet although I didn't add sugar! So, it really can be done by substituting with sweet fruit (they contain natural sugar) like banana and blueberries.
The only minus point of using baking soda is that you have to quickly bring the batter to the steamer or oven fast. Otherwise, they lose their leavening power and the cake may not rise.
That's it! Have fun making cakes with baking soda!