Cook onions in butter over medium heat, stirring occasionally until onions are tender and begin to brown. Sprinkle with flour and mix immediately. Gradually stir in 1 cup broth. Heat to boiling, stirring constantly. Stir in remaining broth, water and Worcestershire sauce. Heat to boiling and then reduce heat. Simmer uncovered for 5 minutes.
Place sliced bread in the bottom of a bowl and cover with soup. Top with your favorite cheese and place under the broiler until melted and bubbly.
by The Savvy Kitchen