Put rack in the center of the oven. Preheat oven to 450°F.
On a baking sheet, mix all veggies, balsamic vinegar and oil. Add salt and pepper. Cook in the oven for about 20 minutes until the veggies are tender, stirring a few times during cooking. Remove skin from the tomatoes and cut in dice.
In a saucepan, bring to boil the chicken stock, veggies and lentils. Let simmer about 5 minutes or until veggies and lentils are very tender. In a blender, reduce the soup to a creamy puree. Add more stock if needed. Adjust seasoning.
Serve this soup as a main dish. You can serve a piece of cheese with Naan bread.