Few dishes embody comfort and elegance like French Onion Soup. Deeply caramelized onions, rich broth, and bubbling cheese unite in this iconic dish.
The savory depth of French Onion Soup is only as good as your stock. Build from a strong base, and every spoonful will reward you with robust, soulful flavor.
Key Players in This French Onion Soup Recipe
- Yellow or red onions – The soul of the soup, they caramelize into a sweet, golden base full of complexity.
- Beef stock – Adds richness and umami; choose a high-quality or homemade version for best results.
- Dry white wine or vermouth – Lifts the flavors, balancing the sweetness of the onions with acidity.
- Fresh thyme – Introduces earthy herbaceous notes that complement the onions perfectly.
- Gruyère cheese – Melts to a nutty, golden finish, forming the iconic topping that defines the dish.
- French baguette – Crisps up into the perfect vessel for that molten, savory cheese crown.
How to Make This Savory Classic
Begin with a mountain of thinly sliced onions and sauté them slowly in olive oil and butter until they’re golden and deeply caramelized.
Add garlic, a sprinkle of sugar, and cook a little longer for depth. Deglaze with dry wine, scraping up all the flavorful bits stuck to the bottom.
Stir in the rich beef stock, fresh thyme, and bay leaves. Let the soup simmer slowly so all the flavors meld into a deep, savory broth.
Toast thick slices of baguette, then top them with Gruyère and Parmesan. Broil until the cheese bubbles and browns just at the edges.
Ladle the soup into bowls and crown each one with a golden, cheesy toast. Alternatively, assemble it all in oven-safe bowls and broil for that rustic French finish.
Tips and Variations to Elevate Your Soup Game
For deeper flavor, try mixing both beef and chicken stock. A splash of brandy near the end adds subtle warmth and complexity. If your stock is mild, a spoon of beef bouillon can bring it to life—opt for Better Than Bouillon for dependable flavor.
Swap Gruyère for Comté or Emmental if needed. Want a vegetarian version? Use caramelized onions with a strong mushroom or vegetable broth and skip the brandy.
For a gluten-free twist, sub the baguette with your favorite GF bread, toasted until sturdy enough to hold that gooey cheese.
How to Store and Reheat Leftover French Onion Soup
Let the soup cool completely, then store in an airtight container in the fridge for up to four days. The flavor deepens with time, making leftovers even more rewarding.
To reheat, warm gently on the stove until hot. Store the toasted bread and cheese separately, and broil fresh servings when you’re ready to eat. If freezing, skip the bread and cheese topping—just freeze the soup in batches, then reassemble when serving for best texture.
French Onion Soup
Ingredients
- 1/2 cup dry vermouth or dry white wine
- 2 tablespoons brandy optional
- 2 cloves garlic minced
- 4 tablespoons extra virgin olive oil
- 1 tablespoon fresh thyme leaves a few sprigs of fresh thyme, or 1/2 teaspoon dried thyme
- 1 teaspoon sugar
- 2 tablespoons butter
- 8 slices 1 inch thick French bread or baguette
- 6 large red or yellow onions about 3 pounds
- 1/2 teaspoon freshly ground black pepper
- Sprinkling grated Parmesan cheese
- 2 bay leaves
- 8 cups beef stock chicken stock, or a combination of both
- Kosher salt to taste
- 1 1/2 cups grated Gruyere cheese
Instructions
- Peel and thinly slice the onions lengthwise to yield approximately 10 cups. In a heavy-bottomed 5 to 6-quart pot, heat 3 tablespoons of olive oil over medium heat. Add onions and stir to coat thoroughly. Cook, stirring often, for 15 to 20 minutes until softened.
- Raise the heat to medium-high and add the remaining tablespoon of olive oil along with the butter. Continue to cook, stirring regularly, until the onions begin to brown, approximately 20 to 40 minutes depending on the equipment and onion variety.
- Sprinkle the sugar and 1 teaspoon of salt over the onions. Continue caramelizing for another 10 to 15 minutes until deep brown. Stir in the minced garlic and cook for one additional minute.
- Pour in the vermouth or wine to deglaze the pot, using a wooden spoon to lift browned bits from the bottom and sides. Add stock, bay leaves, and thyme. Bring to a gentle simmer, cover, and reduce the heat to maintain a low simmer. Cook for 30 minutes.
- Season the soup with salt to taste and stir in the freshly ground black pepper. Discard bay leaves. If using, add brandy at this stage.
- While the soup simmers, prepare the bread. Preheat the oven to 450°F and line a baking sheet with foil or parchment paper. Brush both sides of each slice of French bread with olive oil, using about 1 1/2 tablespoons total. Toast in the oven until lightly golden, 5 to 7 minutes. Flip slices, top with Gruyere and a sprinkling of Parmesan, and return to the oven to melt and slightly brown the cheese.
- To serve, ladle the hot soup into bowls and float a slice of cheese-topped toast on each. Alternatively, place soup in oven-safe bowls or a casserole, top with the toast and cheese, and broil at 350°F until the cheese is bubbly and golden, about 10 minutes.
