Soak the porcini mushrooms in the sherry for about 3 hours.
Then steam the mushrooms that have not been squeezed in some of the mushroom stock for about 1/2 hour. In the meantime, clean the soup vegetables and cut them into very fine strips. Sauté them in the butter and deglaze with the rest of the forest mushroom stock. Add the porcini mushrooms with the cooking stock and season the broth to taste. Simmer gently until the vegetables are cooked (3 - 5 minutes at most).
Arrange on deep soup plates and sprinkle with the herbs of your choice.