- Heat the oil in a pan on medium/low heat.
- When hot, add the chopped onion.
- Fry till soft, add the cumin powder and the bay leaf.
- Add the celery, followed a couple of minutes later by the carrots, celery root and potatoes (keep on a very low heat).
- Cover the pan and sweat for several minutes, stirring occasionally to prevent sticking or burning.
- Add the remaining vegetable stock, and simmer until the vegetables are cooked.
- Leave to cool.
- Once cool, blend the soup, add salt and pepper to your liking, adjust water if necessary.
- Reheat and serve with fennel leaves as garnish.