Instructions

1. Roughly chop the fennel and leek. Keep the fronds of the fennel.
2. Heat the oil in a heavy-based saucepan over medium heat. Add the leek and gently sauté for 8 minutes, stirring regularly.
3. Meanwhile, peel the kohlrabi and parsnip, then cut them into small cubes.
4. Add them to the pot, together with the fennel, then add the caraway seeds and stir for a couple of minutes.
5. Pour in the stock and simmer for about 20 minutes, until the veggies are tender.
6. Using a hand-held blender or liquidiser, process the mixture until you get a smooth, velvety soup. Add more stock if it's too thick.
7. Add the apple cider vinegar. Taste, then season with salt and pepper, if needed.
8. Chop the fronds and scatter on top of the soup when served.