Description
A classic French Onion Soup featuring deeply caramelized sweet onions simmered in rich beef stock, topped with toasted crusty French bread and melted Gruyere and mozzarella cheese. This comforting soup combines savory flavors with a cheesy, bubbly finish under the broiler, perfect as a hearty appetizer or main dish.
Ingredients
Scale
Main Ingredients
- 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, optional)
- 8 cups beef stock (can substitute chicken or vegetable stock)
- 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
- Prepare the Onions: Heat the olive oil in a large, heavy-bottomed pot over medium heat. Halve, peel, and thinly slice the onions, then add them to the pot and stir well to coat with oil.
- Caramelize the Onions: Add the brown sugar and Worcestershire sauce. Cook the onions, stirring every few minutes, until they become deep golden brown and richly caramelized. This process deeply develops the soup’s sweet and savory flavor.
- Add Garlic: Stir in the minced garlic and cook until fragrant, about 1 minute, to infuse the soup base with aromatic depth.
- Incorporate Butter and Flour: Add the butter to the pot and sprinkle in the flour, stirring to combine. This optional step helps thicken the soup slightly and adds richness.
- Deglaze with Wine: Pour in the wine and stir well, scraping up any browned bits stuck to the bottom of the pot. This adds a layer of complex flavor to the soup.
- Add Stock and Herbs: Stir in the beef stock along with the fresh thyme bundle and bay leaf. Bring the soup to a gentle simmer, allowing the flavors to meld and the soup to warm through.
- Season: Add kosher salt and black pepper to taste. Adjust seasoning as needed for balance.
- Remove Herbs and Portion: Discard the thyme stems and bay leaf. Ladle the hot soup into heat-safe bowls or crocks.
- Add Bread and Cheese Topping: Top each bowl with toasted French bread slices, then sprinkle evenly with shredded Gruyere and mozzarella cheeses.
- Broil to Finish: Place the bowls under the broiler until the cheese melts, browns, and bubbles, creating a golden crust. Serve immediately while hot and cheesy.
Notes
- Use sweet onion varieties like Maui or Vidalia for a naturally sweeter caramelized flavor; yellow or white onions work as well.
- The butter and flour step is optional but helps create a richer, slightly thicker soup.
- Wine enhances flavor but can be omitted for a non-alcoholic version; use additional stock instead.
- Beef stock gives authentic depth, but chicken or vegetable stocks are good substitutes for dietary preferences.
- Ensure bowls or crocks are broiler-safe to prevent cracking during the cheese melting step.
- Toasting the bread beforehand prevents it from becoming too soggy when submerged in the soup.
Nutrition
- Serving Size: 1 cup of soup with bread and cheese topping
- Calories: 350 kcal
- Sugar: 8 g
- Sodium: 850 mg
- Fat: 18 g
- Saturated Fat: 8 g
- Unsaturated Fat: 9 g
- Trans Fat: 0 g
- Carbohydrates: 30 g
- Fiber: 3 g
- Protein: 15 g
- Cholesterol: 40 mg
