French Onion Soup
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Caramelized onions, rich beef broth, and toasty bread topped with melted cheese, French onion soup is the ultimate comfort food.
Most people think of French onion soup as “restaurant food,” but it actually originated as a simple peasant dish made from onions, stale bread, and water. Modern versions of onion soup are more elevated, but it’s still super simple to prepare. The key is patience. The onions need to be cooked low and slow so that they sweeten and turn a rich brown caramel color without burning. In addition to giving the onions the proper time and attention, I add a bit of sugar to enhance the sweetness of the onions, and I also stir in a bit of flour to add body to the broth—two tricks I picked up working in a French restaurant that made the best French onion soup ever. Finally, to add even more flavor, I top the croutons with two types of cheese.
If you don’t have ovenproof crocks for the soup, don’t worry—you can just top your soup with melty cheese toasts or serve them on the side. And if you want to get a head start, go ahead and make the broth and toasts several days ahead of time. When it’s time to eat, simply top the soup with the toasts and cheese and flash the crocks under the broiler. French onion soup pairs well with steak and/or a simple green salad.
What you’ll need to make French Onion Soup
How To Make French Onion Soup
To begin, in a large Dutch oven or soup pot, melt the butter over medium heat. Add the oil, onions, salt, pepper, and sugar.
Cook, stirring occasionally, until the onions are deep golden brown and caramelized, 45 to 55 minutes.
In the beginning, you will only need to stir the onions occasionally. As they start to brown midway through cooking, you’ll need to stir them more frequently. Also, be sure to scrape the fond (or brown particles) from the bottom of the pan.
Add the wine and raise the heat to high.
Cook, stirring with a wooden spoon to scrape any fond from the bottom of the pan, until almost all of the liquid has evaporated and the onions are jammy, 8 to 10 minutes.
Add the flour.
Cook for about one minute to dissolve the flour.
Add the broth, Worcestershire sauce, thyme, and bay leaves to the pot.
Bring to a boil, reduce the heat to a simmer, and cook, covered, for about 30 minutes. Add the sherry, then taste and adjust seasoning if necessary. If the soup needs a deeper flavor, try a few shakes of Worcestershire sauce. If it’s not quite sweet enough, add 1/4 teaspoon sugar.
While the soup simmers, preheat the oven to 400°F and set an oven rack in the middle position. Arrange the baguette slices in a single layer on a baking sheet.
Bake until the bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.
Adjust an oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on a baking sheet and divide the hot soup among the crocks. Be sure the soup is very hot as it won’t warm up much in the oven. Top each crock with 1 or 2 baguette slices (do not overlap slices).
Sprinkle evenly with Gruyère and then Parmigiano Reggiano.
Slide the crocks into the oven and broil until the cheese is melted and bubbly around edges, 3 to 5 minutes. (Alternatively, if using regular soup bowls: Top each toast slice with some cheese and return to broiler to melt, about 2 minutes more. Divide the soup among bowls and top each serving with two cheese toasts.)
Let the French onion soup crocks cool for a few minutes before serving.
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French Onion Soup
Caramelized onions, rich beef broth, and toasty bread topped with melted cheese, French onion soup is the ultimate comfort food.
Ingredients
- 4 tablespoons unsalted butter
- 1 tablespoon vegetable oil
- 3 pounds Vidalia (or sweet) onions (about 5 medium), halved lengthwise and thinly sliced
- ¾ teaspoon salt
- ½ teaspoon freshly ground black pepper
- ¾ teaspoon granulated sugar
- 1 cup dry white wine
- 2 tablespoons all-purpose flour
- 6 cups beef broth
- 1 teaspoon Worcestershire sauce
- ½ teaspoon dried thyme
- 2 bay leaves
- 1 small baguette, cut into ½-in slices
- 1 tablespoon dry sherry
- 8 ounces Gruyère cheese, grated (about 2 heaping cups; look for one imported from Switzerland)
- ½ cup grated Parmigiano Reggiano
Instructions
- In a large Dutch oven or soup pot, melt the butter over medium heat. Add the oil, onions, salt, pepper, and sugar. Cook, uncovered, stirring occasionally with a wooden spoon, until onions are deep golden brown and caramelized, 45 to 55 minutes. In the beginning, you will only need to stir the onions occasionally. As they start to brown midway through cooking, you will need to stir them frequently, scraping the fond (the brown particles) from the bottom of the pan. If the onions are browning too quickly, reduce the heat slightly or add a few tablespoons of water to deglaze the pan and continue cooking.
- Add the wine and raise the heat to high. Cook, stirring with a wooden spoon to scrape any fond from the bottom of the pan, until almost all of the liquid has evaporated and the onions are jammy, 8 to 10 minutes.
- Add the flour and cook, stirring constantly, for one minute.
- Add the broth, Worcestershire sauce, thyme, and bay leaves to the pot. Bring to a boil, reduce the heat to a simmer, and cook, covered, for about 30 minutes.
- While the soup simmers, preheat the oven to 400°F and set an oven rack in the middle position. Arrange the baguette slices in a single layer on a baking sheet and bake until the bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.
- When the soup is finished, remove the bay leaves and add the sherry; taste and adjust seasoning if necessary. If the soup needs a deeper flavor, try a few shakes of Worcestershire sauce. If it's not quite sweet enough, add ¼ teaspoon sugar.
- Adjust an oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on a baking sheet and divide the hot soup among the crocks (be sure the soup is very hot as it won't warm up much in the oven). Top each crock with 1 or 2 baguette slices (do not overlap slices) and sprinkle evenly with Gruyère and then Parmigianno Reggiano. Slide the crocks into the oven and broil until the cheese is melted and bubbly around edges, 3 to 5 minutes. Let the crocks cool for a few minutes before serving. (Alternatively, if using regular soup bowls: Top each toast slice with some cheese and return to broiler to melt, about 2 minutes more. Divide the soup among bowls and top each serving with two cheese toasts.)
- Make-Ahead Instructions: The soup can be made and refrigerated up to 3 days ahead (without toasts or cheese), or up to 3 months ahead and frozen. Toasts can be made (without the cheese) and kept sealed at room temperature for up to 3 days.
Nutrition Information
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- Per serving (5 servings)
- Calories: 642
- Fat: 31 g
- Saturated fat: 17 g
- Carbohydrates: 53 g
- Sugar: 19 g
- Fiber: 4 g
- Protein: 31 g
- Sodium: 1,697 mg
- Cholesterol: 82 mg
This website is written and produced for informational purposes only. I am not a certified nutritionist and the nutritional data on this site has not been evaluated or approved by a nutritionist or the Food and Drug Administration. Nutritional information is offered as a courtesy and should not be construed as a guarantee. The data is calculated through an online nutritional calculator, Edamam.com. Although I do my best to provide accurate nutritional information, these figures should be considered estimates only. Varying factors such as product types or brands purchased, natural fluctuations in fresh produce, and the way ingredients are processed change the effective nutritional information in any given recipe. Furthermore, different online calculators provide different results depending on their own nutrition fact sources and algorithms. To obtain the most accurate nutritional information in a given recipe, you should calculate the nutritional information with the actual ingredients used in your recipe, using your preferred nutrition calculator.
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This is such an excellent recipe with rich flavor. The only thing I did differently is to cut the bread into cubes after toasting in the oven. Then put the bread cubes on a cookie sheet, top with the cheeses and broil. Then slide onto the top the bowl of soup. I also had some left over short ribs that I added at the bottom of the bowl before topping with the soup. Not that it needed it, but it was just to utilize left overs. Another awesome recipe from Jen.
I actually just came back from Paris a few weeks ago and I had no plans this past rainy Saturday morning and I thought, “You know what, I am going to make some french onion soup!” Jennifer the soup was amazing, It was my first time making it and I am SOO PLEASED! It was everything I wanted to be. It was the closest thing possible to the soup I had at one of my favorite restaurants in Paris, so thank you for gifting us with this recipe and easy instructions!
Why sugar? I am certain the classic version does not have sugar.
Hi Frank, the little bit of sugar helps to balance out the other flavors (similar to adding salt to batter when baking).
I can’t remember if I’ve already reviewed this recipe, so apologies if I have, but I’m making this for a fourth time and just wanted to say how delicious it is. Best recipe ever! 😃
So yummy! Now, where do we find those oh so cute crocks? 😉
Glad you liked it! You can find the crocks at Sur la Table.
Ms. Segal: I cannot thank you enough for being my go-to recipe database (for salads, mains and desserts). My all-time favourite meal is YOUR chicken marsala with YOUR Caesar salad (genius to use mayo instead of eggs), and YOUR chocolate cream pie for dessert.
As for this soup, I impulsively bought an entire bag of shallots at a wholesaler yesterday. Do you suppose I could substitute shallots for onions entirely?
Hi Kathryn, thanks for your nice words about the recipes – so glad you like them! Yes, I think you could get away with using shallots for the soup; I’d love to hear how it turns out if you make it!
How many servings can I have from your French onion soup?
This serves 4 to 6.