Ingredients for making Idli
Take one cup of dal and ½ teaspoon of fenugreek seeds in a large bowl and rinse it well under running water. Soak it in water for 4-5 hours. In a separate bowl, take the rava and add water to cover it fully. Let it sit for 10 minutes. The rice grits should settle down and any dust particles will remain in the water. Carefully drain all the water from it. Add fresh water and soak it for 4-5 hours. It is important to soak them both in separate bowls as the rava does not require any grinding.
Once the urad dal is soaked, drain all the water from the dal into a bowl and set it aside. Grind it into a very smooth batter by adding little water (see the tips section below). If you are using Instant Pot for fermentation, transfer the ground dal to the inner pot. If not, transfer it to a large steel container. Fluff up the urad dal batter using clean hands to aerate it. Drain the water from the soaked idli rava. Scoop out a handful of rava in your hand and squeeze out as much water as possible. Add the squeezed rava to the ground dal. Repeat with the rest of rava.
Now mix the dal and rava well using clean hands making sure that they are fully incorporated.
Use your hands to mix the batter well. Place the inner pot in the Instant Pot and cover it with the main lid or glass lid. Set it to yogurt mode for 12 hours. If you use the glass lid, cover it using a clean kitchen towel.
Perfect batter ready to be steamed.
Add salt to the batter and mix well. Lightly grease the idli molds on idli plates. Spoon in the batter to cover about ¾ of the mold. Add 1½ cups of water to the inner pot of the Instant Pot and set it to Saute mode on high to heat water. Once the water begins to boil, press cancel and place the idli stand. Close the Instant Pot lid and set it to the steam mode in the venting position. Keep an external timer and steam for 12 minutes. A separate timer is needed as the Instant Pot timer does not work in the steam function.
Let them sit at room temperature for another 5 minutes in the idli stand. Wet a spoon with some cold water and scoop out the idlis from the molds.