A herbed "sour" like this is wonderful with a rich pate. Make it one week in advance.
- Portion size 500 servings
Sterilize two 16-ounce (500 mL) canning jars and boil disks for 5 minutes or according to manufacturer's directions.
Trim mushrooms. Rinse briefly in cold water, shake off excess moisture and immediately pat dry. Place in large saucepan with water, lemon juice and salt. Cover and bring to gentle boil; reduce heat and simmer for 6 minutes. Drain, discarding liquid.
Meanwhile, in saucepan, combine vinegar, oil, thyme and pepper and bring to boil. Pack mushrooms into prepared jars, leaving 1/2-inch (1 cm) headspace. Cover with boiling vinegar mixture; add 1 bay leaf to each jar. Press out air bubbles, adding more liquid to completely cover mushrooms. Cover jars with disks and seal tightly with screw bands.
Let jars cool, then label and store in cool, dry, dark place for 1 week before enjoying.