How to Make It
Preheat the oven to 350°. In a food processor, combine the bacon, parsley, thyme leaves, 1/4 teaspoon of salt and 1/2 teaspoon of pepper; process to a paste.
Using your fingers, gently separate the turkey skin from the breast and legs. Season the turkey cavities with salt and pepper. Carefully spread the bacon paste under the loosened skin and press gently on the outside of the skin to evenly distribute. Season the outside of the turkey with salt and pepper and tie the legs together tightly with kitchen string.
Scatter the celery, carrots and white onions in a large roasting pan and set the turkey on top. Tightly cover the bird with 2 sheets of oiled foil and roast on the lowest rack of the oven for 2 1/2 hours. Remove the foil and continue to roast for 1 hour, or until the turkey is browned and an instant-read thermometer inserted in the inner thigh registers 170°. Transfer the turkey to a carving board, cover loosely with foil and let rest for 30 minutes or for up to 1 hour.
Meanwhile, strain the pan juices into a bowl. Skim off the fat; pour 1/4 cup of the fat into a large, deep skillet. Add the sweet onion and thyme sprig and cook over moderately high heat until the onion is browned, about 5 minutes. Add the garlic, then stir in the flour. Gradually add the stock, whisking constantly, until smooth. Whisk in the reserved pan juices and simmer the gravy over low heat, whisking often, until no floury taste remains, about 15 minutes. Discard the thyme and garlic. Season the gravy with salt and pepper and transfer to a warmed gravy boat.
Cut the string from the turkey legs and carve the bird. Serve with the onion gravy.
For more great Thanksgiving recipes, menus and pairings, go to our Thanksgiving Recipes page.