French Onion Soup

French Onion Soup is easier to make at home than you might think. You don’t need any special skills, just a few good ingredients and a little patience. It’s a deeply flavorful blend of onions caramelized in butter and slow-simmered in a rich medley of beef broth and white wine, then finished with a splash of Cognac and topped with toasted croutons and bubbly Gruyère cheese.

Many modern French Onion Soup recipes rush the onions or complicate the process with a lot of extra ingredients. This version is simple and classic, focusing on the step that matters most: slowly caramelizing the onions until they turn deeply golden and sweet. It relies on fresh onions, good-quality beef broth, bread, and cheese. Simple ingredients you can find at most grocery stores.

I’ve adapted this French Onion Soup recipe from Julia Child’s magnificent book, Mastering the Art of French Cooking. I’ve made a few slight changes: increasing the amount of white wine, reducing the Cognac, adding fresh thyme and topping the soup with toasted squares of crusty bread (aka croutons), which are less awkward to eat than slices of a standard loaf or baguette. (I did the same in my Vegetarian French Onion Soup recipe.)

“This came out so good! Such a clever idea with the croutons.
Thanks for a wonderful recipe.”

Pat

Recipe at a Glance

• Prep Time: 15 minutes
• Total Time: 1 hour 30 minutes
• Yield: 6 servings
• Skill Level: Moderate

French Onion Soup Ingredients:

• Yellow onions: Look for large, firm onions with tight skins. I prefer yellow onions here, they’re sweet and caramelize nicely, but are more pungent than sweet onions.
• Butter and olive oil: I like to use both to keep the butter from scorching during the onion’s long cooking time, while still adding buttery flavor.
• Dry white wine: Use a crisp wine like Sauvignon Blanc or Pinot Grigio, not a sweet white wine.
• Cognac: You just need a splash, but don’t skip it (unless you don’t drink alcohol). It adds a whisper of warmth and complexity to the broth.
• Beef broth: It’s the second strongest flavor in this soup, so a good-quality broth really matters. I recommend a good bone broth from your favorite grocery store or, better yet, make my Slow Cooker Beef Bone Broth.
• Fresh thyme: Again, thyme adds just a subtle, earthy flavor, but to me it’s essential. If you don’t have fresh thyme, add a little dried thyme.
• Cheese: Look for a good melting, alpine-style cheese. I love either Gruyère or Comté.
• Baguette: Day-old French bread works best. Cutting it into cubes rather than slices distributes the bread and melted cheese instead of creating a single floating layer.

Why This Recipe Works

• Low and slow onion caramelization: Cooking the onions slowly turns their natural sugars into deep, savory sweetness. This step makes or breaks the soup.
• Wine and Cognac balance the richness: White wine brightens the deeply savory broth and a small splash of Cognac adds complexity. I love both of these touches, but you can omit them if you’d rather skip the alcohol.
• Fresh thyme adds that little “something”: A few sprigs add a touch of earthy flavor.
• Large toasted croutons improve the texture: Instead of a large baguette slice, smaller toasted cubes make eating this soup a pleasure.

How to make French Onion Soup

Step 1: Melt butter in a large soup pot; add onion and stir to coat. Cover and cook 15 minutes over low heat.

Step 2: Meanwhile, toast bread squares until crisp and golden brown. Set aside.

Step 3: Stir salt and sugar into onions and increase heat to medium-low; cook and stir 30 to 40 minutes to caramelize onions to a deep golden brown.

Step 4: Add flour; cook and stir 3 minutes.

Step 5: Add thyme. Stir in wine and broth; simmer uncovered 30 to 4 minutes.

Step 6: Remove from heat and stir in Cognac.

Step 7: Preheat broiler. Ladle soup into individual, broiler-safe bowls and top each with toasted bread squares and shredded Gruyere cheese. Broil just until cheese is melted and bubbly. Serve.

The Night I Fell in Love with French Onion Soup

French Onion Soup originated in Paris, France in the early eighteenth century, but I fell in love with it on September 15th, 2001.

It was a Saturday evening and we’d just arrived in Paris with our friends Bryan and Jenn, six months pregnant with their first child. Just four days prior we sat together in London, eyes glued to a television screen in horror as we watched images of planes crashing into the World Trade Center. We were, all of us, in Europe for the first time on a long awaited two-week adventure.

Our train arrived in Paris in the late afternoon and by the time we got to our hotel the sky was dark and our stomachs were growling. In the hotel lobby there were people everywhere. Some were just arriving, like us. Others were in tears, unable to extend their stay with the city’s hotels at capacity, and unable to fly home as planes were still grounded.

We crossed the street to a restaurant recommended by the hotel concierge. Swirls of cigarette smoke and muffled conversations in an unfamiliar language greeted us. But then steaming bowls of rich French Onion Soup, covered in bubbling cheese were set before us. The soup did not heal the uncertainty or sadness of the situation, but it did taste like comfort and hope.

I’ve made French Onion Soup many times since that night in Paris. This version stays close to the traditional method, with slowly caramelized onions, rich broth, toasted bread, and melted cheese, but with a few small adjustments that make it even better to make and enjoy at home.

How to Store

French Onion Soup stores well without the bread and cheese topping. Refrigerate it in an airtight container for up to 3 days or freeze for up to 3 months. Reheat gently on the stovetop, then add fresh croutons and cheese before broiling.