Slice onions thinly and cook in butter until caramelized.
Add beef broth and simmer for rich flavor.
Season with thyme, bay leaves, and black pepper.
Top with toasted baguette slices and melted cheese.
Broil until cheese is bubbly and golden.
A warm and comforting soup for chilly days.
Serve as an appetizer or a light meal.
Capture the essence of French cuisine.