Soak the lentils in cold water overnight and then rinse to remove the black seed coats.
Drain well, put into an electric blender and grind it finely, adding only as much water as is needed to facilitate blending. Make a thick, smooth paste.
Add ginger, asafoetida, green chillies, salt and blend until it becomes white and light.
With wet hands form mixture into flat patties and drop them into hot oil.
Turn them with a spoon until they are light golden brown, then drain on paper towel.
Asafoetida is a flavour enhancer from the dried gum from the rhizome of several species of Ferula that is found in the Himalayan region. It has a fetid smell, but in cooked dishes, it has a smooth flavour reminiscent of leeks. You could substitute with onion or garlic powder.