Classic French Onion Soup

Featured in: Everyday Dinners

This beloved French classic transforms humble onions into something extraordinary through slow caramelization. The process requires patience—about 40 minutes—to achieve that deep, sweet flavor and rich mahogany color that defines authentic onion soup. A simple flour roun thickens the broth slightly, while white wine adds brightness and depth.

The finishing touch is crucial: thick slices of baguette, brushed with olive oil and toasted until golden, then topped generously with Gruyère and broiled until bubbly and browned. The contrast between the savory, deeply flavored broth and the crisp, cheesy topping creates an incredibly satisfying dish that's perfect for cold weather or when you need comfort food.

Updated on Wed, 28 Jan 2026 11:16:00 GMT
Golden, bubbly Gruyère melts over a toasted baguette slice in Classic French Onion Soup. Save
Golden, bubbly Gruyère melts over a toasted baguette slice in Classic French Onion Soup. | fusionspatula.com

The smell of onions turning to gold on a rainy Tuesday afternoon always makes my kitchen feel like a sanctuary. I used to think French Onion Soup was reserved for fancy bistros until I realized the magic only requires patience and a heavy pot. My first batch was a bit too pale but it still tasted like a warm hug. Now I wait for those onions to reach a deep mahogany color before I even think about adding the broth. It is the ultimate slow food exercise for a busy mind.

I once made this for a group of friends during a power outage using a camping stove and one single flashlight. We huddled around the pot listening to the onions sizzle and the sound of the rain against the window. When the cheese finally bubbled under the broiler after the power flickered back on we cheered like we had won the lottery. That night taught me that the best meals are often the ones that take the most time to develop.

Ingredients

  • Yellow Onions: These are the workhorses of the dish and provide a natural sweetness when cooked down.
  • Unsalted Butter: Using butter instead of just oil adds a creamy richness to the caramelization process.
  • Olive Oil: This helps raise the smoke point so your butter doesnt burn while the onions soften.
  • Garlic: A little bit goes a long way in adding a savory depth to the sweet onions.
  • Sugar: A tiny pinch helps the onions brown faster and enhances their natural sugars.
  • Salt: This draws out moisture and seasons the base from the very beginning.
  • Black Pepper: Freshly ground pepper adds a subtle bite that cuts through the richness.
  • All purpose Flour: This creates a light roux that gives the soup a velvety body.
  • Dry White Wine: Deglazing with wine lifts all those delicious browned bits from the bottom of the pan.
  • Beef or Vegetable Stock: Use a high quality stock because it forms the backbone of the entire flavor profile.
  • Fresh Thyme: These woody herbs infuse the liquid with a classic earthy aroma.
  • Bay Leaf: It adds a subtle layer of complexity that you would miss if it were gone.
  • French Baguette: Look for a sturdy loaf that can stand up to the weight of the soup and cheese.
  • Gruyere Cheese: This specific cheese melts beautifully and provides a signature nutty flavor.

Instructions

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Caramelize the onions:
Melt the butter and oil then let the onions cook slowly until they turn a deep amber color.
Season and aromatics:
Stir in the garlic sugar and salt once the onions are soft and fragrant.
Create the base:
Sprinkle the flour over the onions and stir constantly to cook out the raw flour taste.
Deglaze the pot:
Pour in the wine and use your spoon to scrape up the flavorful bits stuck to the bottom.
Simmer the soup:
Add the stock and herbs then let everything meld together over a gentle heat for twenty minutes. Remove the thyme and bay leaf before serving.
Toast the bread:
Brush your baguette slices with oil and broil them until they are crisp and golden.
Assemble the bowls:
Ladle the hot soup into crocks and place a toasted slice of bread on top.
Melt the cheese:
Pile on the grated Gruyere and broil until the top is bubbling and slightly charred.
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Classic French Onion Soup served steaming hot with a rich, dark broth and melted cheese. Save
Classic French Onion Soup served steaming hot with a rich, dark broth and melted cheese. | fusionspatula.com

I remember my youngest niece trying this and declaring that the melted cheese was like a blanket for the soup. We spent the whole dinner trying to see who could make the longest cheese pull without it breaking.

Choosing Your Stock

The choice of stock can completely change the personality of your soup. While beef stock is traditional and rich a mushroom based vegetable stock adds an incredible earthy note. I once experimented with a mix of chicken and beef broth which created a lighter but equally satisfying result.

The Art of Deglazing

Watching the white wine bubble up and lift the brown glaze off the bottom of the pot is my favorite part. That residue is where all the concentrated onion flavor lives. If you skip this step you are leaving the best part of the meal behind.

Serving and Pairing Ideas

This soup is quite filling on its own but it loves a side that offers a bit of crunch or acidity. A simple green salad with a sharp lemon vinaigrette balances out the heavy cheese perfectly.

  • Serve it alongside a crisp glass of wine to cut through the richness.
  • Try adding a splash of sherry right before serving for an extra layer of warmth.
  • Make sure to warn your guests that the bowls stay hot for a long time.
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Deeply caramelized onions and thyme create a savory Classic French Onion Soup under bubbly cheese. Save
Deeply caramelized onions and thyme create a savory Classic French Onion Soup under bubbly cheese. | fusionspatula.com

This soup is a testament to what a little time and a lot of onions can achieve. I hope it brings as much warmth to your table as it does to mine.

Recipe FAQs

Why does caramelizing onions take so long?

Caramelization is a slow chemical process that converts the onions' natural sugars into complex flavor compounds. Rushing this step over high heat will burn the onions rather than caramelize them, resulting in a bitter taste. Low and slow is essential for achieving that deep, sweet flavor and rich color.

Can I make this soup ahead of time?

Absolutely. The soup base actually improves after a day or two in the refrigerator as the flavors continue to develop. Store it in an airtight container for up to 4 days. Add the bread and cheese topping when you're ready to serve, then broil until golden and bubbly.

What type of onions work best?

Yellow onions are ideal for French onion soup—they have the perfect balance of sweetness and pungency. Sweet onions like Vidalia work too but may caramelize faster. Red onions can be used but will give the soup a purplish hue.

Can I freeze French onion soup?

Yes, freeze the soup base without the bread and cheese topping for up to 3 months. Thaw overnight in the refrigerator, reheat gently, and add fresh toppings when serving. The texture may be slightly thinner after freezing.

What cheese alternatives work well?

While Gruyère is traditional, Emmental, Comté, or Swiss cheese make excellent substitutes with similar melting properties. For a stronger flavor, try adding some Parmesan. Avoid pre-shredded cheese, as anti-caking agents prevent proper melting.

How do I get the cheese properly melted and browned?

Use oven-safe bowls and place them on a baking sheet to catch any drips. Broil on the upper rack, watching closely after 2 minutes. The cheese should be fully melted, bubbling, and golden brown with slightly toasted edges.

Classic French Onion Soup

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

Prep duration
15 minutes
Time to cook
75 minutes
Overall time
90 minutes
Created by Liam Johnson

Food Type Everyday Dinners

Skill level Medium

Cuisine type French

Makes 4 Portions

Diet info Meat-Free

What You Need

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
03 1 cup Gruyère cheese, grated

How to Make It

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

Step 03

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

Step 04

Deglaze: Deglaze the pot with dry white wine, scraping the bottom to release any browned bits.

Step 05

Simmer Broth: Pour in stock, add thyme 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 as needed.

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

Broil and Serve: 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 ingredients for allergens and check with a medical expert if needed.
  • Contains dairy (butter, Gruyère cheese)
  • Contains gluten (baguette, flour)
  • For gluten-free preparation, use gluten-free bread and flour
  • For dairy-free preparation, use vegan butter and cheese alternatives

Nutrition details (per serving)

Nutrition facts are estimates for informational reasons and aren't medical guidance.
  • Energy (kcal): 390
  • Fat content: 16 grams
  • Carbohydrates: 43 grams
  • Protein amount: 16 grams