1 small yellow onion, unpeeled and roughly chopped
Turkey neck and giblets
3 sprigs thyme
Turkey drippings from roasting pan
1/4 cup (30 grams) cornstarch
Freshly ground black pepper
Bring six cups (1420 milliliters) broth to a simmer in a medium pot with onion, neck and giblets and thyme. Cover pot and let simmer for two hours. Strain broth through a fine mesh strainer. Skim all but 1/4 cup (60 milliliters) of fat off drippings in roasting pan, then add stock to roasting pan. Place roasting pan over medium heat and bring it to a simmer.
In a small dish, whisk together cornstarch and remaining broth. While whisking gravy mixture, pour in cornstarch slurry. Continue to whisk and simmer until thick. Strain through a fine mesh strainer. Season with salt and pepper and serve.