Heat oil in a heavy pot over a medium flame. When hot, put in the cumin seeds. A few seconds later, put in the garlic. Stir and fry until the garlic pieces turn a medium brown colour. Now put in the onion. Stir and fry until the onion pieces begin to turn brown at the edges. Put in the lentils and the water. Bring to the boil. Cover, turn heat to low and simmer for about an hour or until lentils are tender. (Nearly all of the liquid should have been absorbed, but watch that it doesn't turn completely solid.)

Add the salt and the cayenne. Stir to mix and simmer gently for another 5 minutes.