Rinse the above ingredients in water for about 2-3 hours.Then grind in a blender (with adding water in steps) into a very fine flour.Add salt and keep it aside (to get sour)for 12 hours. Heat the pan and spread a drop of oil on it.When the pan is fully heated, take some flour and spread it on the pan into a round shape.Turn it over so that both sides are cooked well.When it is almost cooked spread a teaspoon of coconut chutney over it.Place some potato curry and roll the dosai on both sides and move it to a plate.