Preparation of Batter

Wash the Idly rice thoroughly until the water runs clear. Soak it in enough water for 4-5 hours.
Wash the urad dal and soak it separately in enough water for 4-5 hours.
After soaking, drain the water from the urad dal. Grind the urad dal in a grinder until it becomes a smooth batter but retains a slightly coarse texture. (You should be able to feel 75% of the coarseness).
Drain the water from the Idly rice and grind it to a smooth batter.
Mix the ground Idly rice and urad dal batter in a large bowl. Add salt to taste. Mix well.
Let the batter ferment overnight or for 8-10 hours in a warm place. The batter should have doubled in volume after fermentation.

Preparation of Tempering

In a large kadai or pan, heat the oil.
Add the jeera (cumin seeds) and let them splutter.
Add the black pepper and sauté for a few seconds.
Add the finely grated or ground ginger to the kadai and sauté for a minute or until the raw smell of ginger goes away.
Now, add the cashews and fry until they are golden brown.
Pour this tempering into the fermented batter and mix well.

Cooking the Idly

Grease small cups or tumblers with ghee.
Pour the batter into the greased tumblers, filling them up to 3/4th.
Place these tumblers in a steamer or Idly cooker.
Steam the Idlys for about 30 minutes or until a toothpick inserted into the Idly comes out clean.
Once done, remove it from the steamer and let it cool for a couple of minutes.
Using a knife, gently run it around the edges of the tumbler to remove the Idlys.

Serving

Serve the Kanchipuram Idly hot with coconut chutney, sambar, or any other accompaniment of your choice.
Enjoy your delicious Kanchipuram Idly!