Take Rice + urdad dal + Methi seeds in one bowl.Than soak them in two glass for 4 to 5 hours.Rinse the rice a couples of times and keep a side. Before grinding strain the water from soaked Methi seeds+Rice+Urdad dal. Keep it for grinding.You get a batter which is light and fluffy.You can keep for less or more times and this will depend on the temperature conditions on your city.

7 Medium sized potatoes in two cup water for 5 to 6 whistles in the pressure cooker.The pressure settles down on its on in the cooker remove the lid. Then peel them and chop them.Also slices the onion and chop the green chillies,ginger and coriander leaves.Heat oil.Add mustard seeds and add half teaspoon cumin seeds.Add two slides onion,curry leaves, green chillies and ginger.The onions till they soften than turmeric powder and mix very well.Add boiled chopped potatoes and add salt and mix well

Lightly stir the batter before you begin to make dosa.Heat a stick pan.Some oil using a stick pan.Keep the flame to low while spreading better. Spread the better in a circular on the pan.cover the dosa with a lid and let it cook.Cook the dosa base becomes golden and crisp.You see the base has become golden,the potatoes masala on the dosa.You can spread it.Now fold the dosa and serve.