Wash and rinse the urad dal for 2-3 times. Add fenugreek seeds and fill the bowl with enough water. Soak the dal for 6-7 hours or overnight.
Get a bowl and add sago to it. Wash and rinse with the water. Fill the bowl with enough water and let it soak for 6-7 hours or overnight.
Add idli rava in a seperate bowl. Wash and rinse multiple times. Let it soak for 6-7 hours or overnight with enough water.
The next day, drain the water from urad dal and sago. Transfer it to the grinding jar. Grind it to a smooth paste by adding cold water little at a time. Transfer the paste into a big vessel.
Drain all the water from idli rava. Squeeze out the excess water by pressing rava between your palms. Add this rava to the urad dal paste. Mix everything with your hands. Keep it in a warm place for 8-10 hours.
Add salt to the batter and mix it again. Fill the idli cooker with enough water and make it boil.
Meanwhile, grease the idli mold with little oil or butter. Pour the batter into the molds. Place the molds into the idli cooker carefully. Put the lid on and let it steam for 15 minutes on a medium flame.
Turn off the heat and wait for 5 minutes. Remove the lid and get the idli molds out. Let them rest utside for 5 minuts.