Porchetta-Flavored Spatchcocked Turkey

Ingredients

• 3 large onions, roughly chopped, divided
• 3 large carrots, peeled and roughly chopped, divided
• 4 ribs celery, roughly chopped, divided
• 12 thyme sprigs, divided
• 1/2 tablespoon black peppercorns
• 1 tablespoon fennel seed
• 1 teaspoon red pepper flakes
• 4 medium cloves garlic
• 1/2 cup fresh sage leaves
• 1 whole turkey, butterflied according to these instructions, backbone, neck, and giblets reserved
• 2 tablespoons vegetable oil, divided
• Kosher salt and freshly ground black pepper
• 1 1/2 quarts homemade or store-bought low-sodium chicken or turkey stock
• 2 bay leaves

Directions

1. Set an oven rack in the middle position and heat the oven to 450 degrees F (230 degrees C). Cover a rimmed baking sheet with aluminum foil, then spread two-thirds of the onions, carrots, celery, and thyme sprigs over it. Set a wire rack right over the vegetables.
2. In a food processor, or with a mortar and pestle, work the peppercorns, fennel seed, red pepper flakes, garlic, and sage leaves together until you have a coarse paste. Stop to scrape the sides when needed so everything gets evenly mixed.
3. Blot the turkey well with paper towels. Coat it all over with 1 tablespoon (15ml) oil, then season every surface generously with salt and black pepper. If the turkey is brined, salted, or kosher, skip the salt. With your hands, gently loosen the skin from the breast and leg meat, taking care not to tear or detach it. Slide three-quarters of the herb paste beneath the skin, spreading it as evenly as you can over the meat and breaking up any thick pockets. Smear the remaining herb paste over the underside of the turkey.
4. Fold the wing tips behind the back. Set the turkey on the rack, making sure it fits within the edges, and press on the breastbone to help the breasts lie a little flatter.
5. Move the turkey to the oven and roast, turning the pan from time to time, until an instant-read thermometer reads 150 degrees F (66 degrees C) in the thickest part of the breast and at least 165 degrees F (74 degrees C) in the thighs, about 1 hour 20 minutes.
6. As the turkey cooks, prepare the jus. Coarsely cut up the reserved neck, backbone, and giblets. Warm the remaining 1 tablespoon (15ml) oil in a 3-quart saucepan over high heat until it shimmers. Add the chopped turkey pieces and cook, stirring now and then, until they take on light color, about 5 minutes. Stir in the remaining onions, carrots, and celery, and keep cooking, stirring occasionally, until the vegetables begin to soften and brown in places, about 5 minutes longer. Pour in the chicken stock, then add the remaining thyme sprigs and the bay leaves. Bring everything to a boil, lower the heat to the gentlest simmer, and cook until the liquid has reduced by half, about 40 minutes. Pour the jus through a fine-mesh strainer into a 2-quart liquid measuring cup, then discard the solids. Remove fat from the surface of the broth. Add salt and pepper to taste, cover, and hold warm.
7. Once the turkey is done, take it out of the oven and move the rack onto a clean baking sheet. Rest the turkey at room temperature for 20 minutes before carving. Pour the juices accumulated in the pan through a fine-mesh strainer into a liquid measuring cup. Spoon off and discard extra fat, then whisk those juices into the jus.
8. Carve the turkey and serve it with the jus.