French Onion Soup
This French onion soup is a timeless favorite that transforms a few simple ingredients into something rich and elegant. Thinly sliced onions are slowly caramelized until deeply golden and sweet, which gives the soup its signature flavor. They’re then simmered in savory beef broth with a splash of wine or vinegar for added depth. To finish, the soup is topped with a slice of toasted baguette and a generous layer of melted Gruyère or Swiss cheese, broiled until bubbly and golden. Perfect for chilly evenings or special dinners, this dish brings classic bistro vibes right to your table.
Ingredients
- 3 pounds yellow onions 3-4 large onions
- 3 tablespoons unsalted butter
- 1 tablespoon extra virgin olive oil
- 2 cloves garlic minced
- 2 tablespoons all-purpose flour
- ½ cup dry white wine
- 6 cups low sodium beef broth or stock
- ½ teaspoon salt or to taste
- ¼ teaspoon black pepper or to taste
- 4 sprigs fresh thyme or 1 teaspoon dried thyme
- 2 bay leaves
- 8 slices baguette
- 2 ounces Gruyere cheese shredded
Instructions
- Slice the onions into even ¼-inch thick rings or half-moons for uniform cooking and the best caramelization. In a large Dutch oven or another heavy-bottomed pot, heat the butter and olive oil over medium heat until the butter is melted and the mixture is hot and shimmering.
- Add the sliced onions to the pot and begin cooking, stirring every few minutes to prevent sticking. Let the onions cook slowly for 25 to 30 minutes, until they become deeply golden, very soft, and sweetly caramelized. As the onions near the end of their cook time, stir them more frequently to prevent burning and ensure they brown evenly without scorching.
- Once the onions are caramelized, stir in the minced garlic and flour. Cook for about one minute, stirring constantly to eliminate any raw flour taste and help the soup thicken slightly later on.
- Pour in the white wine and stir as it simmers for 1 to 2 minutes, scraping up any browned bits from the bottom of the pot. These bits add depth and richness to the final flavor of the soup.
- Add the beef broth or stock, a pinch of salt and pepper, thyme sprigs or dried thyme, and bay leaves. Increase the heat and bring the mixture to a gentle simmer. Once simmering, reduce the heat to maintain a low, steady bubble. Let the soup cook uncovered for about 30 minutes, stirring occasionally to develop the flavor and allow it to reduce slightly.
- While the soup simmers, preheat your oven to 400 degrees Fahrenheit. Arrange slices of baguette on a baking sheet and toast them in the oven for 5 to 6 minutes, or until the edges are crisp and golden brown. This creates the perfect base for the melted cheese topping.
- Taste the soup and adjust the seasoning with more salt and pepper if needed. Remove and discard the bay leaves and thyme sprigs before serving.
- Preheat the oven broiler to 425 degrees Fahrenheit. Set four oven-safe soup bowls on a sturdy rimmed baking sheet. Carefully ladle the hot soup into each bowl, then place two toasted baguette slices on top of each one, with the more toasted side facing down. Generously sprinkle shredded Gruyere cheese over the bread.
- If your bowls are not broiler-safe, simply flip the baguette slices over on the baking sheet, top them with Gruyere, and broil them separately for 2 to 4 minutes until the cheese is melted and lightly browned. Serve the cheesy toasts alongside the soup.
- Place the baking sheet with the filled soup bowls under the broiler for 2 to 4 minutes, watching closely to prevent burning. When the cheese is melted and bubbling with golden edges, remove the bowls carefully. Garnish with fresh thyme if desired, and serve immediately. Be cautious—the bowls will be extremely hot after broiling.
Notes
To make this recipe vegetarian, simply swap out the beef broth for vegetable broth. This substitution still delivers rich flavor while keeping the soup meat-free and perfect for a vegetarian-friendly meal.
If you don't have Gruyere cheese on hand or prefer another option, white cheddar makes a great alternative. It melts well and brings a sharp, savory note to the dish. For even more depth of flavor, try adding a small sprinkle of grated Parmesan on top of the shredded cheese before broiling.
To prepare this soup ahead of time, you can cook the entire soup and toast the baguette slices up to one day in advance. Store the toasted bread in an airtight container at room temperature so it stays crisp. Let the soup cool and transfer it to a sealed container in the refrigerator. When you're ready to serve, reheat the soup on the stovetop until hot. Then top each bowl with the toasted baguette slices and shredded cheese, and broil according to the recipe instructions until the cheese is melted and bubbly.
If you don't have Gruyere cheese on hand or prefer another option, white cheddar makes a great alternative. It melts well and brings a sharp, savory note to the dish. For even more depth of flavor, try adding a small sprinkle of grated Parmesan on top of the shredded cheese before broiling.
To prepare this soup ahead of time, you can cook the entire soup and toast the baguette slices up to one day in advance. Store the toasted bread in an airtight container at room temperature so it stays crisp. Let the soup cool and transfer it to a sealed container in the refrigerator. When you're ready to serve, reheat the soup on the stovetop until hot. Then top each bowl with the toasted baguette slices and shredded cheese, and broil according to the recipe instructions until the cheese is melted and bubbly.