Rinse the idli rice, urad dal, and fenugreek seeds separately and soak them in water for 4-6 hours.
Drain the water and grind the rice, dal, and fenugreek seeds separately to a smooth paste. Mix them together, add salt, and let the batter ferment for 8-10 hours.
Grease the idli molds with oil and pour the batter into each mold.
Add water to the Instant Pot, place the trivet inside, and stack the idli molds on top of the trivet.
Close the lid, set the vent to sealing, and pressure cook on high for 10 minutes.
Allow natural pressure release for 5 minutes, then manually release any remaining pressure.
Carefully remove the idli molds, let them cool slightly, and then unmold the idlis.
Serve hot with chutney and sambar.
Notes:
Ensure the batter is well fermented for soft and fluffy idlis. You can also use a wet grinder for better results.