Classic French Onion Soup Recipe
Sweet caramelized onions, fresh thyme and a rich beef or vegetable broth come together under a crunchy crouton and bubbly gruyere. A cozy, classic French onion soup you can make meatless or not.
Equipment
- oven-safe soup bowls (12 to 16 ounces)
Ingredients
Soup
- 3 medium red onions (thinly sliced, about 3 cups)
- 3 medium yellow or sweet onions (thinly sliced, about 3 cups)
- 2 tablespoons olive oil
- 4 tablespoons unsalted butter
- 2 cloves garlic (minced)
- ½ cup dry white wine (or dry vermouth)
- 32 ounces beef or vegetable broth (bone broth is great here)
- 1 tablespoon white wine vinegar
- 1 teaspoon beef or vegetable bouillon base
- 1 tablespoon fresh thyme (plus more for garnish)
- ½ teaspoon kosher salt (plus more to taste)
- ½ teaspoon ground black pepper (plus more to taste)
- 2 cups gruyere cheese (shredded, or Swiss)
- 1 tablespoon cornstarch (optional, for thickening)
Croutons
- 6 slices French bread or baguette (½ inch thick)
- 4 tablespoons olive oil
- kosher salt (to taste)
Instructions
Croutons
- Preheat the oven to 425°F. Brush both sides of the bread slices with olive oil and lightly sprinkle with salt.
- Place on a baking sheet and bake until crisp and golden brown, about 15 to 20 minutes, flipping halfway through. Set aside.
Soup
- In a large Dutch oven or soup pot, melt the butter with the olive oil over medium-low heat. Add the onions and cook, stirring occasionally, until very soft and deeply golden, about 40 to 45 minutes. Do not rush this step, and lower the heat if the onions start to burn. Add the garlic for the last minute.
- Add the wine, broth, white wine vinegar, bouillon base, thyme, salt and pepper. Cover and bring to a simmer over medium heat, then simmer for 30 minutes. For a thicker soup, stir together the cornstarch and 1 tablespoon of cold water and stir it into the simmering soup. Season to taste.
Assemble
- Turn the oven to broil and set a rack about 10 inches from the top. Ladle the soup into oven-safe bowls, leaving about ½ inch of space at the top. Top each with a crouton and about ⅓ cup of gruyere.
- Set the bowls on a baking sheet and broil until the cheese is melted and bubbly, watching closely so it does not burn. Garnish with fresh thyme and serve.
Kori's Tips
For more helpful hints, substitution ideas, cooking tips, and other delicious recipes check out my post above.
TIPS: Be patient with the onions. Low heat and time give you sweet, deeply caramelized onions, while high heat burns them and makes the soup bitter. Use oven-safe bowls, and do not worry if the cheese melts over the sides.
VARIATIONS: Try fresh tarragon or marjoram instead of thyme. Use all one kind of onion, swap the white wine for a dry red, or top the croutons with mozzarella or a sprinkle of parmesan along with the gruyere.
MAKE IT FLEX: Use beef broth and beef bouillon for the classic version, or go meatless with a rich vegetable broth and vegetable bouillon.
SERVING SUGGESTIONS: Garnish with thyme, parsley or chives. Serve with extra slices of baguette and a crisp green salad, like a strawberry goat cheese salad or a roasted beet salad.
Nutrition
Calories: 361kcalCarbohydrates: 14gProtein: 18gFat: 15gCholesterol: 15.3mgSodium: 862mgFiber: 2gSugar: 10g
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