Directions 6 steps | 60 Minutes
Heat butter and olive oil in a pot. Once the butter has melted, add the onions and stir over low heat for about 20 minutes or until well caramelized.
Add garlic, dried thyme and black pepper. Stir until aromatic.
Add the vegetable broth, Worcestershire sauce and bay leaf. Cover and simmer for 20 minutes. While the soup is simmering, preheat the oven to 425°F.
Season the soup with salt and pepper to taste. Ladle soup into heat-proof bowls.
Top with a slice of French bread and shredded Gruyere.
Bake for 5-10 minutes at 425°F or until the cheese is melted. Enjoy!