Pour the pan juices into a bowl and skim the fat: reserve 6 tablespoons of the fat. In a large saucepan, mix the fat with the flour to form a paste. In a medium saucepan, warm the Rich Turkey Stock and slowly whisk it into the flour paste. Bring to a boil over moderate heat, whisking constantly. Whisk in the reserved pan juices and simmer over low heat, whisking frequently, until thickened and flavorful, about 25 minutes. Season with salt and pepper and stir in the pecans; transfer to a large gravy boat. Carve the turkey, arrange on a platter and serve with the pecan gravy.