Creamy Cauliflower Soup

Heat 1 can broth to boiling in 3-quart saucepan. Stir in cauliflower, celery, onion, and lemon juice. Heat to boiling; reduce heat to medium. Cover and cook 15 to 20 minutes or until vegetables are tender; do not drain. Carefully pour about half of the cauliflower mixture into blender; Cover and blend in high speed until uniform consistency. Repeat with remaining cauliflower mixture; reserve. Melt margarine in 3-quart saucepan over low heat. Stir in flour. Cook, stirring constantly , until flour is absorbed; remove from heat. Stir in milk and remaining 1 can broth with wire whisk. Stir in onions. Heat to boiling, stirring constantly. Boil and stir 1 minute. Stir in reserved cauliflower mixture, the pepper and nutmeg; cook until hot. Sprinkle with ground nutmeg if desired