Heat oven to 350°F. Melt margarine in medium saucepan over low heat. Stir in flour; cook until mixture is smooth and bubbly, stirring constantly. Stir in all remaining sauce ingredients except cheese. Cook over medium heat for 5 to 8 minutes or until sauce is thickened, stirring constantly. Stir 1/2 the sauce (1 cup) into broccoli mixture; mix well.