In skillet over medium heat, in 1 tablespoon hot margarine, cook chicken for 10 minutes or until browned on both sides. Remove chicken, keep warm. In same skillet, in remaining margarine, cook broccoli, carrots and mushrooms for 5 minutes, stirring often. Stir in soup, milk and pepper. Heat to boiling. Return chicken to skillet. Reduce heat to low, simmer for 5 minutes or until chicken is fork tender. Garnish with lemon slices. Makes 4 servings.