Homemade Turkey Stock

Position rack in top third of oven and preheat to 450 °F. Using heavy cleaver, chop wings into 2-inch pieces. (See Test-Kitchen Tips, below.) Spread wings in roasting pan and roast, turning with tongs after 20 minutes, until deeply browned, about 45 minutes. Meanwhile, in 6-quart stock pot over moderate heat, heat oil until hot but not smoking. Add onion, carrot, and celery and cook, stirring occasionally, until soft, about 10 minutes. Add wings and any pan juices and reduce heat to low. Straddle roasting pan across 2 burners on high heat and cook until browned bits are sizzling, about 1 minute. Add 2 cups cold water and bring to boil, scraping up browned bits with flat wooden spatula or spoon. Pour liquid into pot and add enough cold water to cover ingredients by 1 inch, about 14 cups. Raise heat to high and bring to boil, skimming foam from surface. Add parsley, thyme, peppercorns, and bay leaf. Reduce heat to low and simmer, uncovered, 3 hours, adding water as needed to keep wings covered. Pour stock through fine-mesh sieve into large bowl, discarding solids. If using immediately, let stand until yellow fat rises to surface, 1 to 2 minutes, then skim off and discard fat. If not using immediately, place bowl in larger bowl of iced water. Let stand, changing ice water as it warms, until stock is tepid, at least 30 minutes. Cover and refrigerate until chilled, then scrape off and discard fat. (Stock can be made ahead and refrigerated in airtight container up to 2 days or frozen up to 6 months. Reheat in saucepan over low heat before using for stuffing and turkey.)