Peel and chop the carrot, celery, onion, and garlic.
Measure Your Stock
Measure out the 8 cups of chicken or turkey stock. Having it ready before you start keeps things moving.
Brown the Neck and Giblets
Heat the butter and oil in a saucepan over medium heat. Add the neck and giblets and cook until they're cooked through and have taken on some color.
This step is where much of the flavor in the final gravy actually starts — don't rush it.
Caramelize the Vegetables
Add the chopped vegetables and garlic, and sauté until caramelized, about 15 minutes, stirring occasionally to prevent sticking. Turn the heat down if things are browning too fast.
Deglaze
Turn the heat to medium-high and add ¼ cup of the white wine to deglaze, scraping up the browned bits from the bottom of the pan. Reduce until nearly evaporated, about 5 minutes.
Build the Quick Stock
Add the 8 cups of stock, peppercorns, parsley, thyme, poultry seasoning, and bay leaves. Reduce heat to low and simmer, uncovered, for 1 hour.
Season lightly with salt and pepper. Strain this "quick stock" and set it aside.
Deglaze the Roasting Pan
Remove the turkey from the roasting pan. Pour off the pan drippings and reserve. Place the roasting pan over high heat — straddling two burners if needed — and deglaze with the remaining ½ cup white wine.
Skim and Return the Drippings
Skim all but 2–3 tablespoons of fat from the reserved pan drippings, then return the drippings to the pan.
Make the Roux
Sprinkle the flour into the pan and cook over medium-high heat, stirring and scraping constantly, for 2–3 minutes.
Don't stop stirring here — this is where lumps happen if the flour sits still too long.
Thicken the Gravy
Pour in the quick stock and bring to a boil over medium heat to thicken.
Season and Strain
Taste and adjust the seasoning, then strain through a fine mesh strainer before serving.