||Heat oil in a heavy pot over medium-high heat. Add the lamb cubes and brown on all sides for about 3 minutes.
||Add the onions, carrots, bell peppers, celery and cumin and cook for 2 minutes, stirring frequently.
||Stir in the lentils and 2 cups of water. Sprinkle with pepper and salt. Bring to a boil, reduce the heat to low and simmer, covered, until the lentils are tender but not quite done, stirring occasionally. Depending on the type and freshness of the lentils, this will take about 20 to 30 minutes.
||Garnish with mint leaves and serve immediately.