Onion Soup
["2 Tbsp. unsalted margarine", "2 c. thinly sliced onion (2 medium)", "1 Tbsp. all-purpose flour", "4 c. low-sodium beef broth", "1/8 tsp. ground black pepper", "4 Tbsp. freshly grated Parmesan cheese"]
["In a large saucepan over low heat, melt margarine.", "Add onion and cook, stirring frequently, 15 minutes.", "Add flour and cook, stirring constantly, 1 minute.", "Add broth and pepper; bring to a boil."]
["unsalted margarine", "onion", "flour", "low-sodium beef broth", "ground black pepper", "freshly grated Parmesan cheese"]