Peel and chop the onion into thin slices and set aside.
Wash, peel and grate the sweet potato. In a mixing bowl, combine the flours, grated sweet potato, onion, salt, curry leaves, turmeric, amchur and red chilli powder.
Mix very well and add enough water to make a thick batter.
Heat oil for deep frying. Take a small portion of besan and sweet potato mixture and drop them into the hot oil.
Deep fry the fritters until golden brown and crispy and remove from the oil.
Serve hot with tomato sauce and coffee.
Notes
You can also add ginger garlic paste to make it more flavorful.