Why struggle to make gravy at the last minute on Thanksgiving, when you can make it a day or two in advance! Just reheat in a saucepan over medium heat. The turkey stock can be made, cooled and frozen for up to 6 months.
Preheat oven to 400 degrees.
Sauté turkey wings and necks, celery, onion, and garlic in oil in a roasting pan on top of the stove over medium-high until beginning to brown. Transfer to oven, roast 45 minutes, then turn the wings and necks over and roast an additional 45 minutes.
Add broth to the pan and cook in the oven for 1 hour, or until reduced to 8 cups. Strain stock and set aside.
Melt butter in a large pot over medium heat. Whisk in flour and cook 1-2 minutes, stirring constantly.
Gradually add strained stock, whisking until smooth. Bring to a boil, simmer 2 minutes to thicken, then reduce heat to medium-low; simmer 10 minutes. Finish with vinegar, salt and pepper.