Rinse the rice and the urad dal separately under running water until the rinse water runs clear (typically 3–4 rinses).

Add the 1/2 tbsp fenugreek seeds to the rice, then place the rice (with fenugreek) and the urad dal in separate bowls and cover with plenty of water. Soak both for 4–6 hours.

After soaking, drain both, reserving some of the soaking water for grinding.

Grind the soaked urad dal into a smooth, light paste, adding reserved water little by little until you get a consistency similar to tahini (smooth and slightly airy).

Grind the soaked rice and fenugreek seeds into a coarse paste, adding reserved water as needed; the rice paste should be slightly grainy, not completely smooth.

Transfer both pastes to a large, clean bowl. Mix them together thoroughly by folding or whisking to incorporate air; the combined batter should be thick but slightly pourable/pasty.

Cover the bowl (with a lid or clean cloth) and keep the batter in a warm place to ferment until it has risen and roughly doubled in volume. Fermentation time will vary by temperature (commonly 6–12 hours). If your kitchen is cold, keep the covered bowl in a warm spot (for example, near a warm appliance or in an oven on a very low setting) to help fermentation.

Once fermented and doubled, add salt to taste and mix gently but thoroughly.

Grease the idli moulds with sesame oil. Fill each mould about three-quarters full with batter using a ladle.

Add enough water to the idli steamer or pot to create steam and bring the water to a rolling boil. Place the idli stand inside and cover with the lid.

Steam the idlis for 8–10 minutes with the lid on. If using a pressure cooker without the vent/weight, steam for about 10 minutes.

Turn off the heat and wait until the steam subsides before opening the lid. Let the idli stand sit for 4–5 minutes.

Optionally sprinkle a little cold water over the idlis in the moulds to help loosen them. Use a small knife or spoon to gently loosen and remove the idlis from the moulds.

Serve the idlis warm.