Start by placing the idli dosa rice (or parboiled rice), whole urad dal, and fenugreek seeds in a bowl or deep pan. Rinse thoroughly a few times to eliminate impurities. Add 2.5 cups of water and allow it to soak. In a separate bowl, rinse the thick poha once or twice to remove excess starch. Drain the poha and add it to the same bowl containing the rice, dal, and fenugreek seeds. Stir everything together and cover. Let the mixture soak undisturbed for 5 to 6 hours.

Once soaked, strain the mixture, keeping the water aside to adjust the batter consistency later. Transfer half of the soaked mixture to a wet grinder jar, adjusting batch size depending on the capacity of your grinder. Add ½ cup of water and grind the ingredients until smooth—the rice should resemble the texture of idli rava. Transfer the batter into a large mixing bowl. Repeat the same process with the remaining mixture, using the rest of the water as needed. Ensure the batter is well-blended and smooth but not runny. If your grinder heats up, let it cool before resuming. Add rock salt and sugar to the batter and stir until fully incorporated. In warmer climates, sugar can be skipped.

Cover the bowl with a lid and let it sit in a warm, draft-free area for 8 to 9 hours or longer, depending on the ambient temperature. Once fermented, if desired, add baking soda and mix thoroughly—this is optional and helpful if the batter hasn’t risen sufficiently or you prefer extra soft idlis.

Grease the idli moulds with oil to prevent sticking. Pour the fermented batter into the moulds, filling each cavity just enough to allow room for the idlis to rise while steaming. Prepare your steamer or cooker by adding 2 to 2.5 cups of water and bringing it to a boil. Carefully place the idli stand inside the steamer or cooker. For electric steamers and idli cookers, cover and steam. If using a pressure cooker, remove the whistle and close the lid securely.

Steam the idlis for about 12 to 15 minutes. Cooking time may vary slightly depending on your equipment. When a toothpick inserted into the center comes out clean and dry, the idlis are done. Allow them to rest for a couple of minutes before removing. Use a wet spoon or butter knife to gently lift the idlis from the moulds. Transfer the warm idlis to a casserole or insulated container to keep them soft and hot.

Serve poha idlis alongside freshly made coconut chutney and a comforting bowl of onion sambar or mixed vegetable sambar for a satisfying South Indian meal.