1Melt butter in 3-quart saucepan over medium-high heat. Cook bell pepper and mushrooms in butter, stirring occasionally, until bell pepper is crisp-tender.
2Stir in flour, salt and pepper. Cook over medium heat, stirring constantly, until bubbly; remove from heat. Stir in milk and broth. Heat to boiling, stirring constantly. Boil and stir 1 minute. Stir in chicken and pimientos; cook until hot. Serve over rice.