Wash beans and place in a bowl with water to cover. Soak for 8 hours. Drain and rinse.
Put beans and 1 1/3 cup water in food processor or blender and puree. The puree should be very smooth, light and fluffy. If your container is small, do it in batches.
Line a sieve with a double layer of cheesecloth and put the cream of rice cereal in this. Rinse it under cold water until the water runs clear. Squeeze the rice to remove all the water and add it to the bean paste.
Beat this mixture thoroughly by hand. Cover bowl and set in a warm place for 8 to 12 hours to ferment. I do this in my oven with the light on – I don’t have a pilot. If it’s particularly cold in the house, I’ll heat the oven to 150 for a short time then put the batter in and turn off the oven. I generally leave this overnight.
When ready to make the dumplings, stir in the baking soda. Do not overblend – the batter should be foamy and airy. Let the batter rest while preparing the steamer.
Cut out pieces of cheesecloth to fit the indentations of the idli steamer or egg poacher. You can use each piece twice by using it on both sides, but I find that this makes the steamer really messy. The pieces should be just larger than the depression. Line the dumpling racks with the cheesecloth.
Bring water to boil in a pan that will fit the steamer. I used my wok with the bamboo steamer or a tall pot that fits my idli steamer.
Spoon about 1/4 to 1/3 cup of batter into each lined depression. This will depend on the size of the “rack” you have especially if you are improvising. Assemble and place in steamer. Steam for 12-15 minutes until a toothpick comes out clean. Remove from steamer.
Pick up each dumpling and carefully remove cheesecloth. These can be placed in a covered dish or another steamer to keep warm while you make the rest.
If reusing the cheesecloth, place them with the smooth side up and brush lightly with oil.
The traditional way to serve these is to make an indentation in the middle with your finger and pour in some light (not toasted) sesame oil. We just eat them plain or with spicy chutney.
Leftover batter can be used to make Uttapapum .