Classic French Onion Soup

Featured in: One-Pot Comfort Bowls

This beloved French classic transforms humble yellow onions into something extraordinary through slow caramelization. The process takes about 35-40 minutes, developing deep, sweet flavors that form the foundation of a truly remarkable bowl. Onions are cooked slowly in butter and olive oil until they turn a rich mahogany color, then deglazed with white wine to capture every bit of flavor.

The broth simmers with aromatic thyme and bay leaf, while thickened slightly with flour for body. The finishing touch—the iconic cheese-topped crouton—gets broiled until golden and bubbly, creating that irresistible cheese pull. Perfect for cold weather entertaining or a cozy weekend dinner.

Updated on Tue, 27 Jan 2026 20:03:09 GMT
A close-up of Classic French Onion Soup in a rustic bowl, featuring deep brown caramelized onions swimming in rich golden broth, topped with a toasted baguette slice and a thick, bubbly layer of melted Gruyère cheese. Pin it
A close-up of Classic French Onion Soup in a rustic bowl, featuring deep brown caramelized onions swimming in rich golden broth, topped with a toasted baguette slice and a thick, bubbly layer of melted Gruyère cheese. | plumcrescent.com

Classic French Onion Soup is the ultimate comfort food, celebrated for its rich, umami-packed broth and iconic melted cheese topping. This bistro staple transforms simple yellow onions into a sweet and savory masterpiece through slow caramelization, offering warmth and sophistication in every spoonful.

A close-up of Classic French Onion Soup in a rustic bowl, featuring deep brown caramelized onions swimming in rich golden broth, topped with a toasted baguette slice and a thick, bubbly layer of melted Gruyère cheese. Pin it
A close-up of Classic French Onion Soup in a rustic bowl, featuring deep brown caramelized onions swimming in rich golden broth, topped with a toasted baguette slice and a thick, bubbly layer of melted Gruyère cheese. | plumcrescent.com

The secret to an exceptional French Onion Soup lies in patience. By slowly cooking the onions until they reach a dark, jammy consistency, you develop a depth of flavor that defines the dish. Once deglazed with white wine and simmered with fresh herbs, the result is a hearty soup that tastes even better than what you would find in a Parisian café.

Ingredients

  • 3 large yellow onions, thinly sliced
  • 1 tablespoon unsalted butter
  • 1 tablespoon olive oil
  • 2 cloves garlic, minced
  • 1 teaspoon sugar
  • 1/2 teaspoon salt
  • 1/4 teaspoon freshly ground black pepper
  • 2 tablespoons all-purpose flour
  • 1/2 cup dry white wine
  • 1.2 liters (5 cups) beef or vegetable stock
  • 2 sprigs fresh thyme
  • 1 bay leaf
  • 4 slices French baguette, about 1 inch thick
  • 1 tablespoon olive oil (for bread)
  • 120 g (about 1 cup) Gruyère cheese, grated
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Instructions

Step 1: Caramelize the Onions
In a large pot or Dutch oven, heat butter and olive oil over medium heat. Add sliced onions, stirring to coat. Cook, stirring frequently, until onions are soft and deeply caramelized, about 35–40 minutes. Add sugar and salt halfway through to help with caramelization.
Step 2: Add Aromatics
Add garlic and cook for 1 minute until fragrant. Sprinkle in the flour and cook, stirring, for 2 minutes to thicken slightly.
Step 3: Deglaze and Simmer
Deglaze the pot with white wine, scraping the bottom to release any browned bits. Pour in the stock, add thyme and bay leaf. Bring to a simmer, then reduce heat and cook uncovered for 20–25 minutes. Remove thyme and bay leaf. Season with pepper and additional salt as needed.
Step 4: Prepare the Topping
Preheat oven broiler. Arrange baguette slices on a baking sheet, brush both sides with olive oil, and toast under the broiler until golden, about 1–2 minutes per side.
Step 5: Broil and Serve
Ladle hot soup into oven-safe bowls. Top each with a toasted baguette slice, then cover generously with grated Gruyère. Place bowls on a baking sheet and broil for 2–3 minutes, or until cheese is melted, bubbly, and golden brown. Serve immediately.

Zusatztipps für die Zubereitung

To achieve a more complex flavor profile, you can use a combination of beef and chicken stock. Ensure you use high-quality oven-safe bowls for the broiling step, and always scrape the bottom of the pot during deglazing to incorporate the flavorful browned bits into the broth.

Varianten und Anpassungen

While Gruyère is the classic choice, you can substitute it with Emmental or Comté for a similarly delicious melted crust. For a heartier and more robust soup, consider adding a splash of brandy or dry sherry along with the white wine during the deglazing process.

Serviervorschläge

This soup is best enjoyed immediately while the cheese is still bubbly and hot. It pairs beautifully with a crisp white wine or a light red wine, which helps balance the richness of the savory broth and the melted cheese.

The Classic French Onion Soup rests under a perfectly broiled, golden-brown crust of Gruyère cheese, with chunks of toasted bread floating on the savory broth beside sprigs of fresh thyme. Pin it
The Classic French Onion Soup rests under a perfectly broiled, golden-brown crust of Gruyère cheese, with chunks of toasted bread floating on the savory broth beside sprigs of fresh thyme. | plumcrescent.com

Whether you are looking for a elegant appetizer or a soul-warming main course, this Classic French Onion Soup is a timeless choice. Its combination of sweet onions, savory broth, and golden cheese makes it a rewarding dish that never fails to impress.

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Recipe Questions & Answers

How long does it take to caramelize onions properly?

Onions need 35-40 minutes over medium heat to achieve deep caramelization. Stir frequently to prevent burning. Adding a pinch of sugar and salt halfway through helps draw out moisture and promotes even browning. The onions should turn a rich mahogany color, not just golden brown.

Can I make this soup vegetarian?

Absolutely. Simply substitute vegetable stock for the beef stock called for in the base. The soup will still be deeply flavorful thanks to the properly caramelized onions, white wine deglazing, and aromatic herbs. Many vegetarians actually prefer the lighter vegetable broth version.

What type of cheese works best?

Traditional Gruyère is ideal because it melts beautifully with excellent flavor and creates that classic bubbly, golden crust. Swiss Emmental or French Comté make excellent alternatives if Gruyère isn't available. Avoid pre-shredded cheese, as anti-caking agents prevent proper melting.

Can this soup be made ahead and frozen?

The soup base freezes beautifully for up to 3 months. Let it cool completely, then transfer to freezer-safe containers. Thaw overnight in the refrigerator before reheating. Add the bread and cheese topping just before serving—never freeze assembled soup as the bread will become soggy and texture will suffer.

Why add flour to onion soup?

The flour serves two purposes: it lightly thickens the broth, giving the soup more body and velvety texture, and it helps create a stable emulsion. Cook the flour for 2 minutes after adding it to remove any raw taste before deglazing with wine. For gluten-free versions, use a 1:1 gluten-free flour blend.

What wine pairs well with French onion soup?

A crisp white wine like Chablis, Sauvignon Blanc, or a dry Pinot Gris complements the rich, savory flavors beautifully. If you prefer red, a light-bodied French Beaujolais or Pinot Noir works well. Avoid heavy tannic reds which can clash with the sweet caramelized onions.

Classic French Onion Soup

Rich, comforting French classic with caramelized onions in savory broth, topped with toasted baguette and melted Gruyère cheese.

Prep time
15 minutes
Time to cook
75 minutes
Overall time
90 minutes
Created by Avery Hayes

Recipe type One-Pot Comfort Bowls

Skill level Medium

Cuisine type French

Total made 4 Portions

Dietary details Vegetarian-friendly

Ingredient list

Onions

01 3 large yellow onions, thinly sliced
02 1 tablespoon unsalted butter
03 1 tablespoon olive oil

Soup Base

01 2 cloves garlic, minced
02 1 teaspoon sugar
03 1/2 teaspoon salt
04 1/4 teaspoon freshly ground black pepper
05 2 tablespoons all-purpose flour
06 1/2 cup dry white wine
07 5 cups beef or vegetable stock
08 2 sprigs fresh thyme
09 1 bay leaf

Topping

01 4 slices French baguette, about 1 inch thick
02 1 tablespoon olive oil for bread
03 1 cup Gruyère cheese, grated

How-to

Step 01

Caramelize onions: In a large pot or Dutch oven, heat butter and olive oil over medium heat. Add sliced onions, stirring to coat. Cook, stirring frequently, until onions are soft and deeply caramelized, approximately 35 to 40 minutes. Add sugar and salt halfway through to facilitate caramelization.

Step 02

Add garlic: Add minced garlic and cook for 1 minute until fragrant.

Step 03

Create flour roux: Sprinkle in flour and cook, stirring constantly, for 2 minutes to thicken slightly.

Step 04

Deglaze pot: Pour dry white wine into the pot, scraping the bottom to release any browned bits and caramelized sediment.

Step 05

Build broth: Pour in stock, add thyme sprigs and bay leaf. Bring to a simmer, then reduce heat and cook uncovered for 20 to 25 minutes. Remove thyme and bay leaf. Season with pepper and additional salt to taste.

Step 06

Toast bread: Preheat oven broiler. Arrange baguette slices on a baking sheet, brush both sides with olive oil, and toast under the broiler until golden, approximately 1 to 2 minutes per side.

Step 07

Assemble bowls: Ladle hot soup into oven-safe bowls. Top each with a toasted baguette slice, then cover generously with grated Gruyère cheese.

Step 08

Finish under broiler: Place bowls on a baking sheet and broil for 2 to 3 minutes, or until cheese is melted, bubbly, and golden brown. Serve immediately.

Tools Needed

  • Large pot or Dutch oven
  • Wooden spoon
  • Baking sheet
  • Oven-safe soup bowls
  • Cheese grater

Allergy warnings

Review all ingredients for allergy risks and speak with your healthcare provider if you're concerned.
  • Contains dairy: butter, Gruyère cheese
  • Contains gluten: baguette, all-purpose flour
  • For gluten-free preparation, substitute with gluten-free bread and flour
  • For dairy-free preparation, substitute with vegan butter and cheese alternatives

Nutrition details (per portion)

These details are for reference and shouldn't replace healthcare advice.
  • Calorie count: 390
  • Fat content: 16 grams
  • Carbohydrates: 43 grams
  • Proteins: 16 grams