Mix semolina, salt, and yogurt, add water as needed to make a pancake-like batter. Set aside for at least 30 minutes.
The batter thickens as the semolina absorbs the water. At this point, add a little more water as needed.
Add approximately 3/4 cup of water to the pot. Check to make sure that the water does not touch the bottom plate of the idli stand. Bring to boil.
Lightly grease idli plates with oil.
Add Eno Fruit Salt to the batter and mix well. The mixture will begin foaming. Immediately begin pouring into the Idli trays. Place the stand into the steaming pot.
Cover the pot and steam idles for about 6-8 minutes on medium heat. Insert a toothpick in the center of one idli. If the toothpick comes out clean, remove the stand from the pot. Do not overcook idles, as they will lose their softness and dry out as they cool.
Cool for just a few minutes before removing each individual idli. They should come out easily and not stick to the mold. Idles should be spongy and soft.