Herb-Rubbed Turkey with Roasted-Garlic Gravy

PreparationOne day ahead: Process herbs and garlic in food processor until finely minced. Set aside. Rinse turkey inside and out with cold water; pat dry with paper towels. Trim excess fat. Place turkey in large nonreactive bowl. Starting at neck cavity, loosen skin from breast and drumsticks by gently inserting fingers between skin and meat. Sprinkle kosher salt and pepper under and over skin. Then spread garlic-herb rub under skin and gently press skin to adhere. Lift wing tips up and over back; tuck into turkey. Refrigerate at least 8 hours or overnight. To roast: Let turkey stand at room temperature 1 hour before serving. Set oven rack at lowest position and preheat oven to 350°F. Spread sliced onions on bottom of heavy-bottomed roasting pan and place fitted rack over top. (Or place the turkey directly on bed of onions. They will prevent sticking and flavor drippings.) Brush turkey with grapeseed oil and carefully transfer to rack. Brush one side of double-folded sheet of aluminum foil with grapeseed oil and tent, greased side down, over turkey breast. Place turkey in oven so legs face back of oven and bird, breast side up, faces door. Place wrapped garlic on oven rack. Roast 45 minutes. Remove garlic from oven. Remove foil from turkey and turn pan around. Roast until thermometer inserted in thickest part of thigh registers 170°F and juices run clear when thigh is pierced with fork (see note below), about 1 hour 15 minutes. Transfer turkey to platter and reserve pan drippings. Let turkey stand 20 minutes before carving. Prepare gravy while turkey rests: Pour drippings into 4-cup glass measure, and skim off fat that rises to surface, reserving 1 tablespoon fat (see tip below). Add enough broth to drippings to measure 3 cups. Separate roasted garlic cloves. Squeeze pulp into small bowl and mash well with fork. In medium saucepan over medium heat, heat reserved fat. Add garlic and flour, and cook, whisking constantly, until lightly browned, about 30 seconds. Gradually whisk in broth mixture. Bring to boil over high heat, whisking constantly, and remove from heat. Carve turkey and serve with gravy. NOTE:To gauge turkey doneness, an instant thermometer should be inserted into the thickest part of the thigh. The U.S. Department of Agriculture recommends that this meatiest part be cooked to 180°F. Other cooking experts believe that the bird can safely be removed from the oven at 170°F, because the internal temperature will rise an additional 10 degrees as the turkey rests. I (the author), however, follow another school of thought, which asserts that, since bacteria is killed instantly at 160°F, the turkey need only be cooked to 165°F. At this point the juices should run clear. To read more about cooking turkeys and food safety, check out our Thanksgiving guide or usda.gov. TIP: To easily separate fat from pan drippings, place zip-top plastic bag inside 4-cup glass measure. Let drippings cool slightly, so they will not melt bag, pour in, and let stand 10 minutes (fat will rise to top). Seal bag and carefully snip off one bottom corner. Drain drippings into measuring cup, stopping before fat reaches opening.