Put the lentils and chopped garlic in a saucepan with 400ml water. Bring to the boil, turn down to a gentle simmer and cook, stirring often, for about 20 minutes, until the mixture is thick and the lentils are starting to break down, adding a little more water if necessary.
Meanwhile, bring a pan of water to the boil, drop in the watercress and cook for a minute or so, just until it’s completely wilted. Drain and leave to cool in a colander. When it’s cool enough to handle, squeeze out all the water, then chop fairly finely.
Heat the oil in a frying pan over a medium heat. Add the onion and fry for about 10 minutes, stirring often and keeping the heat at medium. The idea is to get the onion to start to caramelise and brown just a little. Combine the cooked lentils with the chopped watercress and cooked onion. Season if you like, and serve hot with rice or bread.
Subscribe to our newsletter.