Firstly, prepare the batter for Masala Dosa. Then wash and immerse the rice, fenugreek seeds and urad dal in separate vessels for approximately 6-8 hours. When the rice and urad dal are immersed well, grind them in a mixer till the mixture get smooth. Take the batter of both the ingredients in a bigger vessels. Add salt to it.
For making the filling of the dosa, heat oil in a thick pan and let the mustard seeds splutter. Then add finely chopped onions, curry leaves, green chilies and stir-fry them until the onions changes its color.
Then add a pinch of salt and turmeric powder and mix it well. After that, take the boiled potatoes and add them to the stir-fried onions and mix them well. Add some water into the mixture and allow the potatoes to mix it well for around 4 minutes. When it gets ready, switch off the stove.
Now heat a dosa tawa in a low-medium flame. Add a little oil in the dosa tawa. Wait for the tawa to get hot.
Then add and spread the batter of urad dal and rice in a circular motion.
When the color of dosa's edges turns into brown, low the flame and sprinkle few drops of oil on the dosa sides.
Then put 2 tbsp of filling. Fold the dosa. Serve this delicious hot Masala Dosa with coconut chutney and sambhar.