Activate the yeast with mixing 40ml water, let it rest for 15 minutes. Mix 150ml water with rice flour until smooth. 

In another bowl, mix 150 ml boiling water with sugar. Then add the syrup into the flour mixture, let it cool completely. Add the yeast, mix well. (You must let the mixture cool down, or it will kill the yeast)

Cover the bowl with plastic wrap, let it rest in room temperature for 1 to 2 hours. The mixture supposed to have many bubbles in it, which mean is ready.

Brush little oil in a plate, pour the mixture in and steam it under high heat for  20-25 minutes.