Clean and boil sweet potatoes. Let it cool peel out the skin. Using vegetable grater grate the boiled potato and keep aside.

Take a mixer grinder add soaked rice, grated sweet potato,green chillies, ginger, cummin seeds and curry leaves.Grind in to a smooth paste.

Transfer to another bowl add required amount of salt and little water mix well. Make dosa after two hours.

Cook till the dosa become golden and crispy. Remove from tawa. Transfer to serving plate.