Fry the onion in the oil until golden, and then stir in the spices. Fry for a few minutes, and then add the carrots, zest and stock. Simmer until the carrots are tender.
Roughly chop the tomatoes, and strip the leaves from the mint sprigs. Put both in a blender or food processor, and pour the cooked vegetables and stock on top.
When cool enough, process until smooth. Sieve, or not, as you wish. You can enrich the soup with crème fraiche or yoghurt, if you wish, or swirl in some buttermilk or smetana (sour cream), when you serve it. The soup can also be served chilled.
© 2000 Frances Bissell. All rights reserved.