
Melt butter in a large pot over medium heat. Add sliced onions and cook, stirring occasionally, for 30-40 minutes, or until deeply caramelized.
Stir in garlic and cook for 1 minute. Add flour and cook for another minute, stirring constantly.
Pour in beef broth, dry red wine, thyme, bay leaf, salt, and pepper. Bring to a boil, then reduce heat and simmer for 20 minutes.
Preheat broiler. Ladle soup into oven-safe bowls. Top each bowl with a slice of crusty bread and a generous amount of grated Gruyère cheese.
Broil for 2-3 minutes, or until cheese is melted and bubbly.
Remove from broiler and let cool slightly before serving. Garnish with fresh parsley if desired.
Serve immediately and enjoy the rich and satisfying flavors of this classic soup.
This soup is amazing! The depth of flavor is incredible, and the cheese pull is irresistible. A perfect comfort food recipe!
This is the real deal! The patience required to caramelize the onions is totally worth it. The depth of flavor in this soup is incredible. My family devoured it.