Classic French Onion Soup

Featured in: Easy Starts & Side Plates

This traditional French onion soup delivers deep, savory comfort through perfectly caramelized onions cooked low and slow until golden brown. The rich broth gets body from a flour roux and depth from white wine, herbs, and quality stock. Each bowl is crowned with crusty baguette slices and generous Gruyère that broils into a golden, bubbly crust. The total hands-on time is just 15 minutes, with the remaining cooking time mostly unattended while onions develop their signature sweetness and color. For best results, use yellow onions and take time with the caramelization step—this is where the complex flavor develops.

Updated on Wed, 28 Jan 2026 13:06:00 GMT
Golden, bubbly Gruyère cheese melts over a toasted baguette slice in Classic French Onion Soup. Save to Pinterest
Golden, bubbly Gruyère cheese melts over a toasted baguette slice in Classic French Onion Soup. | ovenmargin.com

The afternoon sky was darkening into twilight as I stirred the pot of slowly caramelizing onions, filling my kitchen with their sweet, fragrant aroma. French Onion Soup came into my life during a particularly cold January when I craved something that would warm me from the inside out. I remember standing over the pot, glass of wine in hand, watching the transformation of simple ingredients into something magical. That first spoonful, breaking through the blanket of melted Gruyère into the rich broth below, convinced me this would become a staple in my cooking repertoire.

Last winter, I made this soup for my neighbors after they helped shovel my driveway during a particularly heavy snowfall. We gathered around my dining table, steam rising from our bowls as conversation flowed easily between spoonfuls. One of them actually closed his eyes with the first bite, which might be the highest compliment a cook can receive. The room grew quiet except for the occasional scrape of spoons against bowls and murmurs of appreciation.

Ingredients

  • Yellow Onions: I discovered through many batches that yellow onions provide the perfect balance of sweetness and savory flavor when caramelized, creating that distinctive rich base.
  • Gruyère Cheese: This might seem like a splurge ingredient, but its nutty complexity and perfect meltability makes it irreplaceable for that authentic golden crust.
  • Dry White Wine: Once I forgot this ingredient and the soup lacked that certain brightness that cuts through the richness, so now I always keep a bottle of Sauvignon Blanc handy just for cooking.
  • Fresh Thyme: The fragrant oils released from fresh thyme sprigs provide an earthy note that dried simply cannot replicate.

Instructions

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Patience with Caramelization:
Heat butter and olive oil in a heavy Dutch oven, then add your thinly sliced onions and prepare for the longest, most rewarding 35-40 minutes. Youll know theyre ready when they collapse into a deep golden-brown tangle that smells like heaven itself.
Building the Base:
Once your onions have reached that perfect caramel color, add the minced garlic just until fragrant, then sprinkle in flour and cook for two minutes. This little roux will give your soup body without turning it gluey.
The Deglazing Magic:
Pour in that white wine and listen for the satisfying sizzle as you scrape up all those flavorful brown bits from the bottom of the pot. Those caramelized bits are concentrated flavor bombs youll want in your soup.
Simmering to Perfection:
Add your stock, thyme, and bay leaf, then let everything mingle and marry for about 25 minutes at a gentle simmer. The kitchen will fill with an aroma that draws people in from other rooms.
The Crowning Glory:
Ladle your soup into oven-safe bowls, top with oil-brushed toasted baguette slices and a generous blanket of Gruyère. Watch closely under the broiler as the cheese transforms into a bubbling, golden crust.
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A steaming bowl of Classic French Onion Soup features caramelized onions and a crusty bread topping. Save to Pinterest
A steaming bowl of Classic French Onion Soup features caramelized onions and a crusty bread topping. | ovenmargin.com

My daughter, typically skeptical of anything with onions, tried this soup on her sixteenth birthday when I convinced her it was a sophisticated choice for her celebration dinner. The look of surprise on her face when she realized shed been missing out all these years was priceless. Now its become our tradition whenever she comes home from college - her first request as she drops her bags at the door.

Making It Your Own

While traditional French Onion Soup has a particular way about it, Ive found joy in subtle variations that still honor its essence. Sometimes I add a splash of cognac alongside the wine for special occasions, or use a combination of onion varieties - adding a red onion to the mix creates beautiful color contrast and slightly different flavor notes. The soup itself is forgiving and welcomes these little touches that make it uniquely yours.

Serving Suggestions

Theres something wonderfully theatrical about serving French Onion Soup, especially when entertaining. I bring the bowls to the table still bubbling from the broiler, warning everyone not to burn their tongues in their eagerness. A simple green salad with a bright vinaigrette makes the perfect counterpoint to the soups richness, and crisp apple slices can cleanse the palate between spoonfuls.

Timing and Preparation

The beauty of this soup lies in its unhurried nature - you simply cannot rush greatness. I often make the base on Sunday afternoons when the house is quiet and I can enjoy the gradual transformation of the onions while catching up on a podcast or chatting with family. The soup base actually improves after a day or two in the refrigerator, making it perfect for planning ahead.

  • If making ahead, store the soup base separately and toast the bread and add cheese just before serving for the best texture contrast.
  • For weeknight efficiency, slice all your onions the day before and store in an airtight container in the refrigerator.
  • Let guests add their own cheese if preferences vary - some might want a lighter topping while others prefer a more substantial cheese crown.
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Classic French Onion Soup served in a rustic bowl, garnished with thyme and melted Gruyère. Save to Pinterest
Classic French Onion Soup served in a rustic bowl, garnished with thyme and melted Gruyère. | ovenmargin.com

This soup has taught me that sometimes the simplest ingredients, given time and attention, create the most profound flavors. Its a delicious reminder that good things come to those who wait.

Common Recipe Questions

How long does it take to caramelize onions properly?

Caramelizing onions takes about 35-40 minutes over medium heat. Stir frequently and add a pinch of sugar and salt halfway through to help the browning process. Don't rush this step—it's where the deep, sweet flavor develops.

What cheese works best for French onion soup?

Gruyère is traditional for its nutty flavor and excellent melting properties. Emmental or Comté make excellent French alternatives. For Italian variations, try fontina or provolone.

Can I make this soup vegetarian?

Absolutely. Simply substitute vegetable stock for the beef stock. The soup will still be rich and flavorful thanks to the caramelized onions, wine, and herbs. Use vegetarian cheese as well.

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 bread and cheese when serving.

What wine should I use?

A dry white wine like Sauvignon Blanc, Pinot Grigio, or a dry French white works well. Avoid overly oaky wines as they can overpower the delicate onion flavor. Use a wine you'd enjoy drinking.

Why add flour to the soup?

The flour creates a light roux that slightly thickens the broth, giving the soup more body and a velvety texture. Cooking the flour for 2 minutes before adding liquid removes any raw flour taste.

Classic French Onion Soup

Rich, comforting French classic featuring deeply caramelized onions in savory broth, topped with toasted baguette and golden bubbly Gruyère cheese.

Prep Time
15 min
Time to Cook
75 min
Time Required
90 min
Published by Ryan Mitchell


Skill Level Medium

Cuisine French

Makes 4 Number of Servings

Diet Details Meatless

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, 1 inch thick
02 1 tablespoon olive oil
03 1 cup Gruyère cheese, grated

How-To Steps

Step 01

Caramelize the Onions: In a large pot or Dutch oven, heat butter and olive oil over medium heat. Add sliced onions and stir to coat. Cook, stirring frequently, for 35-40 minutes until onions are deeply caramelized and tender. Add sugar and salt halfway through cooking to enhance caramelization.

Step 02

Build the Flavor Base: Add minced garlic to the caramelized onions and cook for 1 minute until fragrant. Sprinkle in the flour and stir continuously for 2 minutes to create a light roux.

Step 03

Deglaze and Add Liquid: Pour the white wine into the pot, scraping the bottom with a wooden spoon to release all browned bits and fond. Add the stock, thyme sprigs, and bay leaf, then bring to a simmer.

Step 04

Simmer the Soup: Reduce heat to low and simmer uncovered for 20-25 minutes. Remove the thyme sprigs and bay leaf. Season with black pepper and additional salt to taste.

Step 05

Prepare the Bread: Preheat the oven broiler. Arrange baguette slices on a baking sheet, brush both sides lightly with olive oil, and toast under the broiler for 1-2 minutes per side until golden brown.

Step 06

Assemble and Top: Ladle hot soup into oven-safe bowls. Place a toasted baguette slice on top of each bowl and generously cover with grated Gruyère cheese.

Step 07

Finish Under the Broiler: Place bowls on a baking sheet and broil for 2-3 minutes until the cheese is melted, bubbling, and golden brown. Serve immediately.

Kitchen Tools

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

Allergy Details

Be sure to review every ingredient for potential allergens. Always get professional advice if you're unsure.
  • Contains dairy from butter and Gruyère cheese
  • Contains gluten from baguette and all-purpose flour
  • Suitable for vegetarian diets when using vegetable stock

Nutrition Details (for each serving)

These figures are here for your reference and shouldn’t replace advice from a healthcare provider.
  • Calories: 390
  • Fats: 16 g
  • Carbohydrates: 43 g
  • Proteins: 16 g