Heat oven to 350 degrees. Melt margarine in 2-qt. Saucepan over medium heat. Stir in flour, salt, and pepper. Cook, stirring constantly, until bubbly; remove from heat. Stir in milk and broth. Heat to boiling, stirring constantly. Boil and stir 1 minute. Stir in remaining ingredients. Pour into ungreased 2-qt. Casserole or square baking dish, 8x8x2 inches.

Bake uncovered 40-45 minutes or until bubbly. Garnish with parsley sprig, if desired.