French Onion Soup
["3 onions, thinly sliced", "2 Tbsp. butter", "1 Tbsp. flour", "3 c. beef stock or 3 c. water plus 4 beef bouillon cubes", "salt and pepper to taste", "1 to 3 tsp. Worcestershire or A.1. sauce, as desired", "French bread", "grated Parmesan cheese or Mozzarella slices"]
["Cook onions in butter until soft and slightly browned. Sprinkle with flour.", "Stir and cook over low heat 3 to 4 minutes. Pour in beef stock and bring to a boil, stirring constantly. Season with salt and pepper as desired.", "Simmer about 20 minutes. Add Worcestershire or A.1. sauce.", "Place thick slices of French bread in ovenproof bowls, pour in soup and top with cheese.", "Brown under broiler.", "Serves 4 to 6."]
["onions", "butter", "flour", "beef stock", "salt", "Worcestershire", "bread", "Parmesan cheese"]