Soak the rice, dal and poha for 8 hours ( overnight).
Drain the water out and grind the dal, poha and rice to make a fine paste.
Keep the paste in a moist place for 4 hours( far from windows or fan) to allow it to get fermented. Mix in a pinch of salt after the paste is fermented.
Heat a thick taw on medium flame. Grease it with 1 tablespoon of soybean oil.
Spread a thin layer of the paste paste on tawa and cook it until it gets brown and crispy.
Heat a separate pan with 2 teaspoons of soybean oil. Add add cumin seeds and onion slices. Fry the ingredients until the onions turn pink in color.
Add green chillies, haldi (turmeric powder) and chopped boiled potatoes. Mix well and sprinkle salt.
Spread the fried masala mixture on the crispy dosa and serve with a coconut chutney.