1. In a 3-quart or larger soup pot, heat the oil over medium heat and add the onion. Sauti until the onion is translucent, 8 to 10 minutes. Add the leek and cook until soft, about 5 minutes more.
2. Add the carrots, celery, lentils, water, bay leaf, thyme, and half of the parsley. Over high heat, bring the soup to a boil. Reduce heat and simmer, covered, until the lentils are tender, about 35 to 40 minutes. Halfway through the cooking, add the diced tomatoes with juice.
3. While the soup simmers, in a small bowl, mix together the remaining parsley with lemon zest, and garlic. Set aside.
4. When the lentils are tender, remove the bay leaf. Add the lemon juice, salt, and pepper. Taste and add more salt if needed. As the final touch, stir in the parsley-garlic mixture. Serve hot, ladled into bowls.
Source: Hannaford fresh Magazine, September - October 2006