INSTRUCTIONS

1. Arrange rack in bottom third of oven, then preheat to 300°F.
2. Add chicken to a large pot (with at least 6 liter capacity). Cover with cold water. Bring to a gentle boil over high heat. Drain and discard the water. This gets rid of any scum that would cloud your broth.
3. Return chicken to the pot, then add mushrooms, celery, onions, carrots, parsnip, garlic, parsley, thyme, bay leaves, vinegar, salt and peppercorns. Fill completely with cold water, about 4 liters. Bring back to a gentle boil, then cover and place on a sturdy baking sheet to catch any drips.
4. Carefully transfer to oven and bake for at least 8 hours, or up to 16 hours. After the first hour, uncover and ensure broth is simmering gently. Small bubbles should reach the surface every few seconds. If broth is completely still, increase oven temperature to 325°F. If broth is boiling, reduce the oven temperature to 275°F. Continue to bake for 7 hours, or more.
5. Remove from oven, then uncover. Using a large slotted spoon, remove as many large pieces from the pot to a colander set over a heat-safe bowl. Set a very fine mesh strainer (or a strainer lined with cheesecloth) over another pot or large heat-safe bowl. Pour broth through prepared strainer. Discard solids. Divide broth between containers in sizes useful to you, up to 1 liter capacity, then let cool completely before refrigerating.