- 3 cups mushrooms (any variety)
- 1 fennel bulb, stalks and leaves only (reserve the bulb for another use)
- 5 celery stalks
- 4 medium to large carrots
- 2 large onions
- 1/4 head of green cabbage
- 1/2 large rutabaga, peeled
- 5 leeks, cut in half lengthwise and washed
- 1 small bunch of fresh flat-leaf parsley (about 15 sprigs)
- 1 head of garlic, cut in half crosswise to expose the cloves
- 12 whole black peppercorns
- 6 whole white peppercorns
- 3 bay leaves
- 6 to 8 sprigs of fresh thyme
Thinly slice the mushrooms, fennel stalks, celery, carrots, onions, and cabbage and place in an 8-quart stockpot. Cut the rutabaga into large chunks and place in the stockpot. Add the remaining ingredients and cover with cold water.
Bring to a boil over high heat. As the stock approaches a boil, skim any impurities that rise to the top with a ladle. Lower the heat and simmer gently for 45 to 60 minutes.
Remove from the heat and cool for 10 to 15 minutes. Ladle through a fine strainer, cool, and refrigerate.