Michel Nischan's Roast Turkey with Potato Pan Gravy

To brine turkey: Combine vegetable broth, kosher salt, agave nectar, onions, thyme, sage and peppercorns in a large pot. Bring to a boil, then reduce heat and simmer for 15 minutes. Let cool to room temperature. Transfer to a 16-quart pot, clean 5-gallon bucket or a brining bag. Add ice water. Submerge the turkey in the brine, breast-side down. Weight the turkey with a plate, if necessary, so it stays submerged. Refrigerate for 12 to 18 hours.

To roast turkey: Remove all the oven racks except one, set in the lowest position; preheat oven to 475 degrees F.

Remove the turkey from the brine and rinse well with cold water. Thoroughly dry with a clean kitchen towel or paper towels. (Discard the brine.) Rub the turkey all over with oil and sprinkle with sea salt. Place on a roasting rack, breast-side up, in a roasting pan. Tuck the wing tips under the turkey and tie the legs together with kitchen string.

Roast the turkey for 30 minutes, rotating the pan back to front halfway through. Remove from the oven and cover the whole turkey with a double layer of foil. Add 2 cups hot water to the roasting pan. Continue roasting, rotating the pan again halfway through, until an instant-read thermometer inserted into the thickest part of a thigh without touching bone registers 165 degrees F, 1 to 1 1/2 hours more. Peek under the foil 15 to 30 minutes before you think the turkey will be done; if it's not browning nicely, remove the foil for the remainder of the roasting time.

Carefully transfer the turkey to a large, clean cutting board; let it rest, loosely covered with foil, for at least 20 minutes before removing the string and carving.

To prepare gravy: While the turkey is roasting, place potatoes in a large saucepan and add water to cover. Bring to a boil. Reduce heat to medium, cover, and cook until the potatoes are very tender, 10 to 15 minutes. Drain.

While the turkey is resting, skim any visible fat from the pan drippings. Place the roasting pan over medium heat. Add broth (or stock) and bring to a simmer, scraping up any browned bits. Transfer to a blender, add the potatoes and blend on high speed for 2 minutes. If the gravy is too thick, add a little broth (or stock or water) to thin to the desired consistency. Return the gravy to the pan and simmer over low heat until hot, about 2 minutes. Season with pepper.

Carve the turkey and serve with the gravy.