Like the dosa, idli has also become a kind of a national dish in India. Though originating from South India, if has aficionados all over the country. It is normally had for breakfast in South India (though occasionally for dinner too). In the rest of the country, it is an anytime snack or a meal replacer. It is considered extremely healthy since it is steamed and contains no oil. Many doctors recommend idli to patients as it is supposed to be light on the stomach but full of carbohydrates.
About 18 years ago, I had taken my father and his brothers and their spouses on a pilgrimage. They were all over 75 years then. The pilgrimage lasted two weeks. Since no homemade food was available (all food from street vendors or restaurants) I was worried in case any of them developed a stomach upset. The simple solution that all of them came up with was to stick to idli. And, thankfully, none of them had a stomach upset. So please go ahead and try this very healthy dish.
It requires an idli mould to prepare. You can google “idli mould images” to get an idea of what this looks like.

Ingredients
3 cups red/brown rice
1 cup split black gram (urad dal, ulutham parupu)
Salt to taste
Method
Soak the rice for about 12 hours (overnight best)
Soak the black gram for 1 hour
Drain and grind the rice into a fine, but grainy, batter (add water as necessary, but the batter should be thick)
Drain and grind the black gram into a fine batter, adding requisite water
Mix both batters  together
Add salt
Adjust water to get a semi-solid consistency
Set aside for 10-12 hours to ferment (the batter will rise, so ensure that the vessel has enough space at the top to accommodate this rise)
Batter is ready
To prepare idli, pour a ladle of the batter into each indentation of the idli mould
Transfer the mould to a pressure cooker (without the weight at the top) – you can also use any other steamer
Steam for about 12 minutes (you will know that the idli is done when a toothpick inserted into the steamed idli comes out clean)
Remove the mould from the pressure cooker
Scoop the idlis from the mould into a casserole
Serve hot with your favourite chutney or sambar
Enjoy!