Ingredients:
Raw rice – 1 cup
Par boiled rice * – 1 cup
Husked black gram (urad) – 1/2 cup
Fenugreek seeds – 1 tsp
Salt – to taste

*Par boiled rice, as it is called in India is not under cooked rice as the name may suggest. It is a variety of rice where the paddy is lightly steamed and then husked . This rice imparts the characteristic golden colour to the dosa. If par boiled rice is not available, use 1more cup of raw rice. Soak 1/2 cup of beaten rice ( poha, aval ) separately and grind with the rice.

For Potato Filling
Potatoes – 1/2 Kg
Oil – 4 Tbsp
Mustard – 1 tsp
Cashew nuts – 1 Tbsp, broken into pieces, (optional)
Green chillies – 4-5, slit
Curry leaves – few
Onions – 350 gms, sliced
Turmeric powder – 1/2 tsp
Salt – to taste
Coriander leaves – 2 Tbsp, chopped.

Coconut Chutney
Grated coconut – 1 cup
Roasted gram – 3 Tbsp
Green chillies – 4-6
Ginger – small piece
Salt – to taste

1. Grind all these to a smooth paste, using water as needed.
2. Seasoning
3. Oil, mustard, curry leaves
4. Prepare the seasoning and add to the chutney.

Method

1. Wash both kinds of rice and soak in water for 4-5 hours.
2. Wash and soak the gram in water, with the fenugreek in another bowl. ( There is a theory that if the urad is soaked for more than 1 hour, it looses its fluffiness. So, many people soak it much later. But this is not quite convenient for those who cannot be at home all the time. I have found a solution to this problem. I soak rice and urad at the same time. But use up all the water in which urad is soaked, for grinding the batter. This ensures that the lightness imparted to the batter by urad is not lost. So, do not use too much water for soaking urad. About 5 cm. above its level should be fine. )
3. Grind the urad and fenugreek to a smooth and light paste. (If any of the soaking water is left over, use it for grinding the rice. )
4. Grind the rice to a smooth pate.
5. Mix both the pastes together. Add salt to taste, and water if needed to form a thick pouring batter.
6. Mix well and keep covered over night.

For Potato Filling

1. Boil, peel and lightly mash the potatoes.
2. Heat oil, add mustard.
3. When it begins to splutter, add cashew nuts ( optional) green chillies and curry leaves.Fry for 1/2 minute.
4. Add onions and fry till they are pale brown.
5. Add turmeric and 1 1/2 cup of water.
6. Simmer for 10 minutes.
7. Add potatoes and salt. Mix well keep covered on a low flame for 3-5 minutes. Mix in the coriander leaves and remove from fire.

To make dosas, stir the fermented batter well. Heat a thick, flat griddle, preferably nonstick, till few drops of water, sprinkled on it sizzle and evaporate quickly. Reduce the fame, pour about 1/2 cup of batter on it and spread quickly with the back of a laddle in concentric circles to a thin pancake. Drizzle some oil all around and on top. Increase the fame to medium and cook till the under side is golden brown. Reduce the flame, cover 1/2 the dosa with the potato filling and fold over the other 1/2. To cover it. Serve immediately with coconut chutney.