Drain the black gram and grind to a paste. Add salt, lemon juice, asafoetida, ginger, green chillies, and curry leaves. Beat into a stiff batter and keep aside.

Crush the cumin seeds, mustard seeds, and dry red chillies coarsely.

Heat the oil in a wok (kadhai); fry the powdered spices with the curry leaves and green chillies for a few seconds.

Beat the yoghurt with this spice mixture, salt, and water. Keep aside.

Heat the oil in a wok; gently lower spoonfuls of the black gram batter and deep-fry the dumplings until golden in colour. Remove and drain the excess oil and transfer the dumplings in a pot of water for just a few seconds. Remove and gently squeeze out the excess water. Repeat till all the batter is used up.

Add the dumplings to the spiced yoghurt and serve cold.

Note: To avoid deep-frying, you can bake the dumplings in greased muffin trays for 45 minutes on moderate heat. They should soak for 1 - 2 hours before serving.