Grind all the ingredients listed under kara masala to a slightly coarse paste. Add a tablespoon of water at a time to grind. Set aside.Wash and soak the ingredients in water for a couple of hours. Once the ingredients are soaked for a couple of hours, grind them in a mixie with the water used for soaking to a thick paste.Transfer the ground paste to a bowl.Add in the kara masala and salt. Mix well. Set aside.Add in chopped onions and coriander leaves. Mix well. If the batter is very thick, thin it out with little water. The consistency of batter should be slightly thicker than idli batter.Heat a dosa griddle until hot on medium flame. Ladle half a cup of batter and spread it on the pan. Sprinkle ¼ teaspoon of oil. Flip the adai once after 30 seconds. Cook the Adai for about half a minute on each side, until golden.Serve hot with a spicy chutney or avial.