Grilled Turkey with Toasted Fennel and Coriander and Fresh Thyme Gravy

Name: Grilled Turkey with Toasted Fennel and Coriander and Fresh Thyme Gravy
Ingredients: 1 12- to 14-pound turkey, rinsed, patted dry; 2 tablespoons fennel seeds; 2 tablespoons whole coriander seeds; 2 teaspoons whole black peppercorns; 1 tablespoon coarse kosher salt; 3 tablespoons olive oil; 3 medium carrots, peeled, cut into 3/4-inch pieces; 3 celery stalks, cut into 3/4-inch pieces; 3 medium parsnips (11 ounces), peeled, cut into 3/4-inch pieces; 1 large onion, coarsely chopped; 1 tablespoon chopped fresh thyme; 1/2 cup reserved turkey fat (and butter if needed); 2 to 3 cups low-salt chicken broth; 1/2 cup all purpose flour; 2 teaspoons Sherry wine vinegar; 1 teaspoons finely chopped fresh thyme; Coarse kosher salt; Freshly ground black pepper