| 6 | portobello mushrooms, gilled |
| 1 | pkg. button mushrooms (8 oz.) |
| Extra-virgin olive oil | |
| 6 | oz. carrots, peeled and chopped |
| 2 | leeks (white and light green parts only), chopped |
| 1 | pkg. dried shiitake mushrooms (.75 oz.) |
| 10 | sprigs fresh parsley |
| 4 | sprigs fresh thyme |
| 3 | garlic cloves, smashed |
| 2 | bay leaves |
| 3/4 | cup dry sherry |
| 10 | cups cold water |
Preheat oven to 425°.
Toss portobello and button mushrooms with oil; roast in a roasting pan until browned, 30–45 minutes.
Transfer mushrooms from roasting pan to an 8-qt. stockpot; drain and discard any excess grease.
Add carrots, leeks, dried shiitakes, parsley, thyme, garlic, and bay leaves to stockpot.
Place roasting pan on the stove top over medium-high heat.
Deglaze roasting pan with sherry, scraping up browned bits from the bottom of the pan.
Pour sherry and browned bits over mushrooms and vegetables in stockpot. Add cold water to cover contents of stockpot by 1 inch. Bring stock to a simmer over medium heat. Simmer stock 1 hour.
Using a fine mesh sieve, strain stock into a large bowl; discard vegetables. In an ice bath, cool bowl of stock to below 40°. Cover stock with plastic wrap; refrigerate.