1. Soak urad dal and rice overnight
2. Grind them to fine paste, add salt and leave it for overnight until it ferments. Once it has risen, stir briefly, and keep it in the fridge.
3.Take small amount of batter in a bowl, add some water and stir well adding salt.
4. Heat a flat pan, pour one ladleful of batter on the pan and spread the batter in concentric circles on medium heat.
5. Add 1tsp oil all around the dosa and cook on high flame until golden brown.
6. Remove form heat and serve with curry, sambar and chutny.