Cheese-Spinach Soup
["1/2 c. chopped onion", "1/2 c. chopped celery", "1/4 c. butter", "1/4 c. flour", "1/2 tsp. salt", "1/8 tsp. pepper", "4 c. milk", "1 (10 oz.) frozen chopped spinach", "1 1/2 c. shredded American cheese"]
["In 3-quart saucepan, cook onion and celery in butter until onion is tender.", "Stir in flour, salt and pepper.", "Add milk all at once.", "Cook and stir until thickened.", "Stir in spinach and cheese. Cook and stir until cheese is melted."]
["onion", "celery", "butter", "flour", "salt", "pepper", "milk", "spinach", "American cheese"]