Mushroom kvass

• 7-8 dried white mushrooms
• 1½ litres (2½ pt) kvass

Soak the mushrooms in water for 30 minutes in an earthenware or enamel container at room temperature, then dice them finely. Combine with the kvass, the chopped onions, celery, parsley and chopped parsnip and then cover and cook over a low heat for 1 hour. Add the bay leaves, dill, coriander and peppercorns and stand for 15-20 minutes in a very low oven (110°C, 225°F, gas mark ¼) or over a low