1. Heat the oil in a large saucepan, and the garlic and fry for 1 minute. Add the eggplant cubes and fry, turning frequently, for 2-3 minutes. Add the drained chickpeas and lentils to the pan with the water or stock and bring to a boil. Lower the heat, cover the pan and simmer for 20 minutes.
2. Add the tomatoes and lemon juice and simmer for a further 45 minutes or until the lentils and chickpeas are really tender. If necessary, add a little more water or stock to maintain about 2-1/2 - 3 pints liquid.
3. Stir in the salt and mint, simmer for a few more minutes and serve.