1 Heat the oil and sweat the onion and garlic until translucent. Add the cabbage, carrot and celeriac and sweat all together.
2 When the vegetables have softened slightly add the stock and the bay leaves and simmer over a medium heat for about 15 minutes. Season the soup with salt and pepper and add marjoram to taste.
3 Clean and slice the ceps. Heat the butter in a frying pan and briefly toss the ceps. Add to the soup shortly before serving.
4 Season the sour cream to taste with lemon juice, salt and pepper. Wash the sorrel, pat dry and cut into thin strips.
5 Place on top of the sour cream and hand separately with the soup.