Description
Classic French Onion Soup made with richly caramelized onions, savory beef broth, and topped with crusty French bread and melted Gruyere and mozzarella cheese. This hearty, comforting soup is perfect for a cozy meal and features layers of deep, complex flavors enhanced by a touch of wine and fresh herbs.
Ingredients
Scale
Sauce 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
For Topping
- 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, preparing to caramelize the onions.
- Prepare the onions: Halve, peel, and thinly slice the onions. Add them to the pot and stir to coat with the oil.
- Caramelize the onions: Add 2 tablespoons light brown sugar and 1 1/2 teaspoons Worcestershire sauce. Cook over medium heat, stirring every few minutes until the onions turn a deep golden brown, about 30-35 minutes.
- Add garlic: Stir in 2 minced garlic cloves and cook until fragrant, about 1 minute.
- Add butter and flour: Stir in 1 tablespoon butter and sprinkle 2 tablespoons all-purpose flour if using, mixing well to thicken the soup slightly.
- Deglaze with wine: Pour in 1 cup of wine (sherry, marsala, or port) and stir, scraping the browned bits from the bottom of the pot to enhance flavor.
- Add stock and herbs: Stir in 8 cups beef stock, add a small bunch of fresh thyme and 1 bay leaf. Bring the soup 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 flavors.
- Remove herbs: Discard thyme stems and bay leaf from the soup.
- Assemble bowls: Ladle soup into heat-safe bowls or crocks. Top each with toasted slices of French bread.
- Add cheese: Sprinkle a mix of 1 cup shredded Gruyere and 1 cup shredded mozzarella cheese evenly over the bread and soup.
- Broil to finish: Place bowls under a broiler until the cheese is melted, browned, bubbly, and slightly crispy on top, about 3-5 minutes.
- Serve: Carefully remove from broiler and serve hot immediately for a delicious, comforting meal.
Notes
- Using beef stock creates a richer, more traditional flavor, but chicken or vegetable stock are great substitutes if preferred.
- Caramelizing the onions slowly over medium heat is key for the deep, sweet flavor; do not rush this step by increasing the heat.
- If you want a gluten-free option, omit the flour and ensure the bread is gluten-free.
- The type of wine used influences flavor; sherry adds nuttiness, marsala adds sweetness, and port adds richness.
- Keep the soup simmering gently to avoid burning the bottom and to develop flavors fully.
- Use heat-safe bowls that can withstand broiling to melt the cheese topping safely.
