In a large pot, add idli rice and the urad dal. Wash 2-3 times thoroughly until the water is no longer turbid/starchy. Add thick poha and pour water to cover the ingredients. Soak the rice and dal for 6 hours at the least.
In a wet grinder, add the soaked rice and dal and grind into a smooth batter. Use the water used to soak the rice and dal. Unless required, don’t add extra water. The batter should be thick. If using a mixie/mixer grinder, grind the batter in batches with ice cold water. It is important to not let the batter heat up by running the mixer continuously.
Remove the batter onto a large container and add salt required (I usually add a tsp of fine salt). Using your hand, mix the batter well. Keep it in a warm place for another 8 hours/leave it overnight untouched. The batter should be doubled up in quantity. Beat it down and store it in the fridge until required. The batter should be not too thick and also not too runny.
How I made –
Add 2 cups of water in the idli steamer/cooker pot (I use an old school Hindalium Idli steamer) and let it come to a boil on high flame.
Take fermented idli batter and if required, add some water. The batter should be thick and pourable but not too runny. Fill the idli mould with the prepared idli batter and set the idli plates on the steamer.
Steam the idlis for 10-12 minutes on medium flame. When the idli steamer opened, idlis should have risen up and look cooked. Switch off the heat and let the idlis stay in the steamer for another 5-mins. Remove the idli plates and sprinkle some cold water all over the idlis. Wait for another 5 mins and gently remove the idlis from the mould.
Serve hot with coconut chutney, sambar and idli podi.