French Onion Soup Sandwich

1. In large saucepan, heat oil. Add onions; cook over low heat until onions are soft and translucent. Turn heat to medium-high; stir in white wine. Cook for 10 minutes.
2.  Add beef stock, thyme and black pepper; bring to a boil. Reduce heat to a simmer; cook for 1 hour. Remove from heat; strain onions, reserving broth.
3. For each serving, place 2 slices cheese on bread slice. Top with about 1/4 cup onions and 2 additional slices of cheese. Place bread slice on top.
4. On heated griddle or nonstick pan, cook sandwich until golden brown on both sides and cheese is melted. Remove sandwich from pan; cut into halves or quarters pieces. Serve sandwich with reserved broth.

Photograph courtesy of the National Onion Association