Wash and soak the rice and poha seperately . Soak the urad dhal with the fenugreek seeds in the refrigerator. Soak them all for atleast 2 hours .
Grind the urad dhal and the poha together to a nice paste. Keeping the urad dhal in the fridge ensures that the mixer does not get heated up.
Transfer to a vessel and grind the rice to a nice paste. Mix this up with the urad dhal batter and a bit of salt and ferment for 6 hours to overnight.
Next day, mix up again and check for salt. The batter should be mildly sour.
Grease the idli plates, and pour the batter into the moulds. Steam them in the idli cooker for about 12 minutes.
Check the idli for doneness, let it rest for a minute or two in the mould. Scoop the idlis out using a sharp spoon and serve with any chutney or Sambar.
You can also make dosa/ Indian crepe with this batter, as with any other idli batter.