HOW TO MAKE IDLI

To make Idli, four parts uncooked rice (Idli rice or parboiled rice) to one part whole white lentil (urad dal, Vigna mungo) are soaked separately for at least four hours to six hours or overnight. Optionally spices such as fenugreek seeds can be added at the time of soaking for additional flavor. 

Once done soaking, the lentils are ground to a fine paste and the rice is separately coarsely ground, then they are combined. Next, the mixture is left to ferment overnight during which its volume will more than double. After fermentation some of the batter may be kept as a starter culture for the next batch. 

The finished idli batter is put into greased moulds of an idli tray or "tree" for steaming. The perforated molds allow the idlis to be cooked evenly. 

The tree holds the trays above the level of boiling water in a pot, and the pot is covered until the idlis are done (about 10–25 minutes, depending on size). A more traditional method is to use leaves instead of molds