1. Finely chop the onion and leek. Heat the oil in a saucepan and sauté them for 30 seconds. Finely dice the carrots and celery. You can also dice 50 g celeriac.

2. Finely chop the sauerkraut. Add it to the saucepan along with the carrots and celery, and cook for 1–2 minutes.

3. Add the paprika and 1/4 tsp salt. Pour in 1 litre water and boil for about 20 minutes.

4. Peel and finely dice the potatoes. Add to the softened vegetables and cook for about 20 more minutes, or until tender. Add a little water if needed. Season with fenugreek, boil for a few minutes and remove from the heat.

5. Beat the egg with the lemon juice in a bowl. Pour in 2–3 ladlefuls of hot stock in a thin stream. Then slowly pour this mixture into the soup in a thin stream, stirring occasionally. The soup is ready to serve.