Put the cooked rice and coconut milk in a blender and blend into a smooth slurry. This is optional, but you can warm up the mixture in the microwave or on the stove until it is just lukewarm (NOT hot), this will help to speed up the fermentation process
Activate the yeast:
In the video, I didn't activate the yeast and it took about 2-3 hours for the batter to ferment
Put a yeast with 1 Tbsp of lukewarm water and 1/4 tsp of sugar. Stir to combine and let it sits for 5 minutes or until it turns bubbly. If it doesn't, your yeast is no longer good or the water you use might be too hot and kill the yeast
Prepare cake batter:
In a mixing bowl, mix rice flour, cake flour, sugar and salt. Whisk to mix. Pour in the blended rice slurry and the yeast mixture. Stir to combine. It will be a sticky paste. If you want to put in food coloring, you can add few drops. Cover and let it ferment for about 45 minutes to 1 hour at a warm place. It may take longer if the temperature is not warm enough. The mixture will be foamy with some bubbles
Steam the cake:
Bring the water in the steamer to a rolling boil. Grease some teacups or metal cups with some oil. Put the cups inside the steamer and let them preheat for 5 minutes
Give the cake batter a stir again and use an ice cream scoop to scoop the batter into the cups. Try to fill the cups all the way to the brim. This will help the cake to crack open a bit
Steam over high heat for 15 minutes. Remove from the steamer and let the cake cools down for 10 minutes and then unmould from the cups and enjoy