4 to 5 pounds assorted chicken parts (legs, wings, thighs) or 1 to 2 chicken carcasses
1 yellow onion, halved with skin still on
2 large carrots, scrubbed or peeled and cut in half
2 celery stalks, cut in half, leaves on
4 garlic cloves, cut in half with skin still on
1 large bay leaf
3 to 5 sprigs fresh thyme
6 stems fresh parsley (large handful)
1 to 2 teaspoons kosher salt
½ teaspoon black peppercorns
1 tablespoon cider vinegar or lemon juice
4 to 5 quarts water
Fennel fronds with or without stem (no bulb)
Place all of the ingredients in a large stock pot (6 to 8 quart) and cover with 4 to 5 quarts of water, to about an inch below the top of the pot. Cover pot and bring to a boil over high heat, skimming off any fatty scum that rises to the top.
Once boiling, remove lid from pot and reduce heat to medium-low; simmer gently for 2 to 4 hours. If using fresh chicken parts, remove the meat after 2 hours and return the bones to the stock. Refrigerate or freeze meat for later use. Add more water if stock reduces too much.
Once stock is done, pour it through a fine mesh sieve and discard everything but the liquid. Let cool and then skim off any remaining fat from the surface. Refrigerate overnight and remove any congealed fat from the surface.
Transfer stock to smaller, airtight containers for storage (2 to 4 cups). Refrigerate for up to 4 days or freeze for at least 2 months.