Ingredients:
For Dosa Batter:
2 cups idli rice
3/4 cup urad dal
1/4 cup cooked rice
1/2 tsp fenugreek seeds
salt to taste
water as required
For Potato Masala:
3 potatoes
1 large onion, chopped
3 green chillies, chopped
1 tsp ginger, finely chopped
1/2 tsp turmeric powder
1 sprig curry leaves
1/2 tsp mustard seeds
1/2 tsp urad dal
salt to taste
oil
Preparation:
For Dosa Batter:
- Wash and soak rice in water for about 4-5 hours.
- Wash and soak urad dal in water for 2-3 hours along with fenugreek seeds.
- In a grinder/ blender, add the drained rice along with cooked rice and grind to a smooth batter adding enough water. Transfer this batter to a large bowl and keep it aside.
- Then grind the soaked urad dal along with fenugreek seeds to a smooth fluffy batter adding enough water.
- Mix this urad dal batter with the rice batter. Add salt to taste and mix well.
- Then keep the batter for fermentation in a warm place for about 8-10 hours( or overnight).
For Potato Masala:
- Pressure cook the potatoes adding enough water till soft for 3 whistles. Peel off the skin and lightly mash them.
- Heat 1 tbsp oil in a pan and splutter mustard seeds and urad dal and add curry leaves.
- Add chopped onion, green chillies and ginger and saute for 2 minutes.
- Add the turmeric powder and salt to taste and saute for few seconds.
- Then add mashed potatoes and 1/2 cup of water and mix well.
- Allow the mixture to boil well and cook for few minutes until the mixture thickens. Check for salt and switch off the flame.
 To Prepare Masala Dosa:
- Heat a dosa tawa/ pan and lightly grease with oil.
- Pour a ladle full of dosa batter in the centre and using the back of the ladle spread to a thin and large circle.
- Drizzle 1/2 tsp of oil over the dosa and when it is cooked and the edges starts browning, place 2-3 tbsp of potato masala over the dosa and fold the dosa.
- Remove it to a plate and serve hot with sambar or chutney…
- You can roll the dosa or fold it into half  or into a triangle…