Soak the ceps in the water for 30 minutes. Drain well, reserving the liquid. Discard the ceps.
In a large saucepan, gently sauté the leek and garlic in the butter until the leek is softened; about 5–6 minutes. Add the white wine and potatoes and cook until the wine has evaporated.
Add the cep stock, bring to the boil, and simmer for 20 minutes until the