Classic French Onion Soup

Today, I’m sharing my favorite version of the famous French Onion Soup, the one I make every winter. It’s a simple, soul-warming recipe full of flavor: caramelized onions, crispy bread, and a golden layer of melted cheese… A timeless French classic I never get tired of!

A Quick Note Before We Start

If there’s one dish that truly warms both body and heart, it’s this French Onion Soup! Perfect for chilly or rainy November days and honestly, for the whole winter season.

I shared a version of this recipe two years ago, but since then, I’ve fine-tuned my method. With just a few small tweaks, it went from good to exceptional: a soup that’s deeply flavorful, rich, and perfectly cheesy and golden on top.

5 Tips for the Best French Onion Soup

Here are the little secrets that helped me make my French onion soup taste just as good as the ones served in the best Parisian bistros!

• Be patient: The onions need time to caramelize slowly , never rush this step! Let them cook gently until they turn a deep golden brown, which can take 40 minutes to an hour. Yes, it’s long… but absolutely worth it for that rich, sweet flavor.
• Deglaze with Cognac (or whiskey): I always deglaze my onions with a splash of Cognac (sometimes whiskey when that’s what I have on hand). It adds incredible depth and a hint of warmth. Don’t forget to scrape up the browned bits (the fond) from the bottom of the pot, that’s where the magic happens!
• Use good-quality broth: Traditionally, French onion soup is made with beef broth, but I also love using homemade chicken or vegetable broth when I have some ready. A good broth makes all the difference, it gives the soup body and depth.
• The bread matters: Make sure to toast your bread really well before adding the cheese. If you skip this step, it’ll turn soggy too fast under the melted cheese. Day-old or slightly stale bread actually works best here, it holds its texture beautifully once baked.
• My secret ingredient: A drizzle of balsamic vinegar (ideally from Modena) adds a touch of acidity and a beautiful dark color to the soup. It balances the sweetness of the onions perfectly.

Recipe Card

French Onion Soup

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4.8 of 44 votes

I’ve been craving for one of my favorite soups for days now: a good French Onion Soup with a cheesy toast on top. This so called soupe à l’oignon gratinée is a great recipe for a starter or a light dinner on cold winter days. 

Prep Time 15 minutes mins

Cook Time 1 hour hr

Total Time 1 hour hr 15 minutes mins

Course Soup

Cuisine French

Servings 4

Calories 381 kcal

Print Recipe

Equipment

• 4 Mini-cocottes ramekins
• 1 Round Dutch Oven

Ingredients

  

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For the soup

• ▢ 6 yellow onions about 1½ lb
• ▢ 2 tbsp olive oil
• ▢ 3 tbsp unsalted butter
• ▢ 2 tbsp all-purpose flour
• ▢ 2 cloves garlic
• ▢ 4 cups chicken broth or beef broth for the traditional version
• ▢ ½ cup dry white wine like Sauvignon Blanc or Chardonnay
• ▢ 3 tbsp Cognac or whiskey
• ▢ 1 a small bundle of herbs such as thyme rosemary, savory, and bay leaf, tied together with kitchen twine
• ▢ Salt and pepper

For the topping

• ▢ 8 slices of baguette day-old or lightly stale bread works best
• ▢ 1 clove of garlic
• ▢ 1 cup grated cheese Gruyère, Comté, or Emmental — or you can use Swiss or Jarlsberg if easier to find

Instructions

 

• Peel and thinly slice the onions. In a large pot or Dutch oven, heat the olive oil and butter over medium heat. Add the onions and cook until they start to turn translucent. Stir in the minced garlic, season lightly with salt and pepper.
  
• Let the onions cook slowly for 40 to 60 minutes, stirring often, until they’re deeply golden, soft, and reduced in volume.
  
• Deglaze with the Cognac (or whiskey) and stir well, scraping up all the browned bits from the bottom of the pot. Let it reduce for about 2 minutes.
  
• Sprinkle the flour over the onions and cook for 1 minute, stirring constantly. Add the white wine and let it reduce for another 2 minutes. Then pour in the broth and add the herbs. Simmer gently for 25 to 30 minutes over low heat.
  
• Slice the baguette and toast the pieces until golden. While still warm, rub each slice with the cut side of the garlic clove for that subtle garlicky flavor.
• Ladle the soup into oven-safe bowls or small crocks. Place one or two toasted bread slices on top, sprinkle generously with the grated cheese,
  
• Broil for 3 to 5 minutes in your oven, until the top is golden and bubbling.
  
• Garnish with a few sprigs of fresh thyme and serve immediately, ideally straight from the oven, piping hot and perfectly cheesy.
  

Notes

Storage

French onion soup keeps well for 3 to 4 days in the refrigerator in an airtight container. Reheat it gently on the stovetop over low heat, or in the oven at 325°F (160°C) but without the bread or cheese. Add the toasted baguette slices and melt the cheese under the broiler just before serving, so the top stays perfectly crisp and bubbly.

Freezing

You can also freeze French onion soup (without the bread and cheese). Pour it into glass jars or freezer-safe containers, leaving a little room at the top for expansion. It will keep for up to 3 months in the freezer. To enjoy later, let the soup thaw overnight in the refrigerator, then reheat it gently before assembling and broiling with the bread and cheese.

Nutrition

Calories: 381kcal | Carbohydrates: 37g | Protein: 10g | Fat: 18g | Saturated Fat: 8g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 6g | Trans Fat: 0.2g | Cholesterol: 33mg | Sodium: 1098mg | Potassium: 251mg | Fiber: 3g | Sugar: 8g | Vitamin A: 710IU | Vitamin C: 8mg | Calcium: 208mg | Iron: 2mg

Tried this recipe?Tag @la.cuisine.de.geraldine on Instagram and let me know how it was!

French Onion Soup Variations — Make It Your Own

French Onion Soup is one of those dishes you can easily adapt depending on the season, the type of broth you have, or simply what’s in your pantry. Here are a few ways to personalize it to your taste:

• Vegetarian Version: Swap the beef or chicken broth for homemade vegetable broth, and keep the butter for that rich, comforting flavor.
• Vegan Version: Sauté the onions in olive oil instead of butter and top the soup with your favorite plant-based cheese before broiling.
• Red Wine Version: Replace the white wine with red wine for a deeper color and slightly bolder, richer flavor — it gives the soup a beautiful amber hue.
• Lighter Version: Skip the cheesy topping and serve the soup as is, with a few crispy garlic croutons on top for a lighter but still delicious option.

What to Serve with French Onion Soup

French onion soup is often enjoyed as a starter, but sometimes I love serving it as a light main course, especially with a simple green salad on the side. Here are a few delicious pairings that work perfectly:

• Croque-Monsieur or Croque-Madame: A toasted French ham and cheese sandwich, the Madame comes with a fried egg on top. Together with the soup, it makes a true bistro-style meal!
• Savory Tart: Try it with a slice of homemade Quiche Lorraine or Zucchini and Feta Quiche for lunch.
• Seasonal Warm Dishes: Serve it with my Roasted Butternut Squash or a simple Mushroom Omelet (I love using chanterelles when they’re in season) pair wonderfully for a cozy dinner.

To stay in that Parisian bistro mood, finish your meal with a French classic: A warm Apple Tarte Tatin topped with a scoop of vanilla ice cream, or a Chocolate Mousse, made the classic way, without butter or cream

FAQ – French Onion Soup

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• The authentic Niçoise salad recipe
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