Description
A classic French Onion Soup featuring deeply caramelized onions simmered in rich beef stock, topped with toasted French bread and a blend of melted Gruyere and mozzarella cheeses. This comforting soup combines sweet, savory, and umami flavors, finished under a broiler to achieve a bubbly, golden cheese crust.
Ingredients
Scale
Soup Base
- 1 tablespoon olive oil
- 3 pounds onions (about 5 or 6 medium onions), thinly sliced
- 2 tablespoons light brown sugar
- 1 1/2 teaspoons Worcestershire sauce
- 2 cloves garlic, minced
- 1 tablespoon butter (optional)
- 2 tablespoons all-purpose flour (optional)
- 1 cup wine (sherry, marsala, or port recommended, optional)
- 8 cups beef stock (chicken or vegetable stock can be substituted)
- 1 small bunch fresh thyme
- 1 bay leaf
- 1 tablespoon kosher salt (or to taste)
- 1/4 teaspoon black pepper
Toppings
- 16 slices crusty French bread, toasted
- 1 cup shredded Gruyere cheese
- 1 cup shredded mozzarella cheese
Instructions
- Heat the oil: In a large, heavy-bottomed pot, heat 1 tablespoon of olive oil over medium heat to prepare for caramelizing the onions.
- Prepare the onions: Halve, peel, and thinly slice 3 pounds of onions. Add them to the pot and stir well to coat with the heated oil.
- Caramelize the onions: Add 2 tablespoons of light brown sugar and 1 1/2 teaspoons Worcestershire sauce. Cook the onions over medium heat, stirring every few minutes to prevent burning, until they turn a deep golden brown and develop sweet flavor, about 30-35 minutes.
- Add garlic: Stir in 2 minced garlic cloves and cook for about 1 minute until fragrant.
- Add butter and flour: Stir in 1 tablespoon of butter and sprinkle 2 tablespoons of all-purpose flour over the onions if using. Mix thoroughly to slightly thicken the soup as it cooks.
- Deglaze with wine: Pour in 1 cup of wine such as sherry, marsala, or port, scraping the browned bits from the bottom of the pot to incorporate extra flavor.
- Add stock and herbs: Stir in 8 cups of beef stock along with a small bunch of fresh thyme and 1 bay leaf. Bring the mixture to a gentle simmer.
- Season soup: Add 1 tablespoon kosher salt (adjust to taste) and 1/4 teaspoon black pepper. Let the soup simmer gently for 15-20 minutes to meld the flavors together.
- Remove herbs: Discard the thyme stems and bay leaf from the soup before serving.
- Assemble bowls: Ladle the hot soup into heat-safe bowls or crocks. Place toasted slices of French bread on top of the soup in each bowl.
- Add cheese: Evenly sprinkle a mixture of 1 cup shredded Gruyere and 1 cup shredded mozzarella cheese over the bread and soup surface.
- Broil to finish: Place the bowls under a broiler for 3-5 minutes until the cheese melts completely, browns lightly, bubbles, and becomes slightly crispy on top.
- Serve: Carefully remove from the broiler and serve immediately while hot for a comforting, flavorful meal.
Notes
- For a vegetarian version, substitute beef stock with vegetable stock.
- Use a mix of Gruyere and mozzarella for ideal melting and flavor; alternatively, Swiss cheese can be used.
- Caramelizing onions slowly is key to developing rich flavor—do not rush this step.
- Broil carefully to avoid burning the cheese topping.
- Leftovers can be refrigerated and reheated gently on the stovetop or microwave.
