• Make the dosa batter: Place rinsed rice in a bowl, cover with water and leave it to soak and hydrate for 4-6 hours. Place the urad dal, (optional chana dal, poha) and fenugreek seeds in a another bowl, rinse well and cover with cold water. Set aside 4 to 6 hours to hydrate.
• Drain rice and dal-fenugreek mixture and save the soaking liquid. Place the rice in a food processor/blender or wet-dry grinder. Add a little soaking liquid to help grind to a smooth paste. Depending on the power of your blender or food processor's power it will take up to 5-7 minutes. I prefer to work in batches to achieve perfect consistency.

  If using rice flour skip the soaking of rice for 4-6 hours and grinding. Simply add enough water to rice flour and lentil paste to make a batter with steady pouring consistency.
• Combine the rice and lentil pastes in a large mixing bowl. Whisk together so both pastes are well incorporated, adding enough water to obtain a medium-thick batter that should have a steady pouring consistency.
• Cover bowl with a kitchen towel and set in a warm place(see detailed description). Leave it to ferment until the surface is frothy, bubbly with a pleasant sour taste, this will take anywhere from 8-16 hours. Check frequently. Stir in the salt before cooking. The batter is ready to use.

  To use later use, transfer the batter to a tightly covered container, and refrigerate.. (Batter will keep for up to a week, refrigerated. Thin with water if necessary.)
• To make dosas, set a griddle or cast-iron skillet over medium heat. Spray or brush with very little ghee or any neutral oil. Ladle ¼-⅓ cup batter in the center of griddle(depending on the size of the pan).
• Using bottom of ladle, quickly spread batter outwards in a circular concentric motion to a diameter of about 6-8 inches. Drizzle ½ teaspoon oil over the top. (with practice it will get faster and even perfectly)
• Allow the dosa to cook and crisp, the outer edges crisp first, then it gets golden all over but not completely. Cook for about 2 minutes, if the center has thick batter cover the dosa with a large lid so the steam will cook it through or carefully flip to cook.
• With a wooden spatula, carefully loosen dosa from griddle. Bottom should be crisp and beautifully golden and the top should be firm and cooked. Serve immediately with the accompaniments. Continue making dosas with the remaining batter one at a time.

Potato Masala Filling (make this before you make the Dosas)

• Warm the oil in a skillet or saute pan over medium heat. Add mustard seeds, urad dal, Chana dal and cumin seeds. Allow for the seeds to sizzle pop and turn slightly golden, about 1 minute, then add onion, salt and green chillies if using.
• Cook, stirring until onions have softened, about 3-5 minutes. Add turmeric, asafetida, ginger, curry leaves.
• Add the water and bring it up to a boil.
• Add the pre boiled potatoes peas if using. Cook, stirring well to combine, until liquid has evaporated, about 3-5 minutes. Mash potatoes a little with the back of a spoon to breakdown any large pieces. Season well with salt if needed, Garnish with chopped cilantro and lemon juice. Potato filling may be prepared up to a day in advance.