Meanwhile, add remaining 2 tablespoons butter to drippings in skillet; melt over medium-high heat. Add onions, carrot and celery; cook 6 to 8 minutes or until softened. Stir in flour; cook 1 to 2 minutes longer or until thickened. Stir in broth; heat to boiling, stirring frequently. Boil and stir 2 to 4 minutes or until thickened. Strain; season with salt and pepper to taste; serve with turkey.