Meanwhile, in 3-quart saucepan, melt butter over medium heat. Add onion; cook about 2 minutes, stirring occasionally, until tender. Beat in flour with wire whisk. Gradually beat in broth and sage. Reduce heat to medium-low; cook about 5 minutes, stirring occasionally, until sauce thickens. Stir carrots, broccoli and turkey into sauce. Spoon turkey mixture into ungreased 2-quart casserole.