French Onion Soup Recipe

French onion soup is in a class all by itself, a timeless dish that feels both rustic and incredibly elegant. It started centuries ago as a simple “poor man’s soup,” little more than onions and water simmered in a pot.

Then, in the 18th century, Parisian cooks worked their magic, transforming it with silky caramelized onions, rich broth, and that now-iconic blanket of gooey, broiled cheese.

Ingredients Needed for the Recipe

Gathering your ingredients is the first step to creating something truly memorable. Here is what you’ll need to build those incredible layers of flavor.

• Unsalted Butter & Yellow Onions: The butter provides a rich base for slowly coaxing the natural sweetness out of a mountain of thinly sliced onions.
• Salt & Granulated Sugar: Salt enhances all the flavors, while a pinch of sugar gives the onions a helpful nudge towards deep, golden caramelization.
• Garlic & Dry Red Wine: Minced garlic adds a fragrant punch, and the red wine deglazes the pot, lifting all the tasty browned bits into the soup for a more complex depth.
• Beef Broth & Chicken Broth: Using a combination creates a richer, more nuanced broth than using just one type, forming the soul of the soup.
• Worcestershire Sauce, Fresh Thyme, & Bay Leaf: These are your flavor boosters, adding savory, herbal, and aromatic notes that make the broth truly sing.
• Balsamic Vinegar: A small splash at the end introduces a subtle, sweet acidity that brightens the entire dish and balances the richness.
• French Bread, Olive Oil, & Cheeses: The sturdy, toasted bread sits atop the soup, ready to absorb the broth, while a trio of Gruyère, Mozzarella, and Parmesan cheeses melts into a glorious, bubbling crust.

The Right Bowls for the Job

That picture-perfect, bistro-style presentation is no accident. True French onion soup is always served in special oven-safe crocks.

These ceramic bowls are designed to withstand the intense heat of the broiler, allowing the cheese to melt and bubble into a beautiful, golden seal. They’re not strictly necessary, but they make the experience feel truly authentic.

How to make French Onion Soup?

Step 1- Soften the Onions

In a large, heavy-bottomed pot, melt the butter over medium-high heat. Add all of your thinly sliced onions and sauté them, stirring fairly often, until they have wilted and become soft and translucent. This initial softening takes about 10 minutes.

Step 2- The Caramelization Process

Now, reduce the heat to medium and stir in the salt and sugar. This is where patience becomes your most important ingredient. You’ll cook the onions for another 35 minutes or so, stirring only every 5 minutes, until they turn a deep, golden brown and take on an almost syrupy consistency.

Step 3- Add Garlic and Wine

Stir in the minced garlic and cook for just 20 seconds, until its fragrance fills your kitchen. Then, pour in the red wine to deglaze the pot, using your spoon to scrape up all the delicious browned bits from the bottom.

Step 4- Build the Broth

Add the beef broth, chicken broth, Worcestershire sauce, fresh thyme sprigs, and the bay leaf to the pot. Give everything a good stir, incorporating the caramelized onions into the liquid.

Step 5- Simmer for Depth

Bring the soup to a gentle simmer over medium or medium-low heat. Let it bubble away for about 20 minutes, stirring occasionally. This allows the flavors to meld together beautifully.

Step 6- Final Flavor Touches

Fish out and discard the thyme sprigs and bay leaf. Stir in the balsamic vinegar, then taste the soup. This is your moment to adjust the seasoning with more salt and freshly ground black pepper if it needs it.

Step 7- Toast the Bread

Preheat your oven’s broiler and position a rack about six inches from the heat source. Brush both sides of the French bread slices with olive oil and place them on a baking sheet. Broil for 2-3 minutes total, flipping once, until golden and toasted. Watch it closely.

Step 8- Assemble and Broil

Place your oven-safe bowls on a sturdy rimmed baking sheet. Ladle the hot soup into each bowl, filling them about two-thirds of the way. Top each one with a slice of the toasted bread.

Step 9- The Cheesy Finish

Generously sprinkle the combination of Swiss, Mozzarella, and Parmesan cheeses over the bread, covering it completely. Carefully transfer the entire baking sheet to the oven and broil until the cheese is magnificently bubbly and spotted with dark golden brown.

Storing and Reheating Your Masterpiece

If, by some miracle, you have leftovers, let the soup cool completely before transferring it to an airtight container. It will keep in the refrigerator for up to three days.

To reheat, simply place the soup in oven-safe bowls and warm in a preheated oven for about 15 minutes before adding fresh cheesy bread and broiling. You can also freeze the soup (without the bread and cheese) for up to three months.

Tips

• Do not rush the caramelization. Those 35-40 minutes are non-negotiable for developing the deep, sweet flavor that defines this soup.
• Use room temperature, freshly shredded cheese for the best melting texture and that perfect, stretchy pull.
• When broiling the bread and the final cheese topping, do not walk away. Oven broilers are powerful, and things can go from perfectly golden to completely burnt in a matter of seconds.
• If you don’t have red wine, you can substitute with a dry white wine or even a splash of additional broth, though the wine adds a wonderful complexity.
• A combination of different onions, like yellow and sweet, can create an even more interesting and layered flavor profile in your soup.

Print Recipe

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French Onion Soup Recipe

Author: Sarah Onida Cooking Method: Stovetop Cuisine: French Courses: Soups

Difficulty: medium Prep Time 20 mins Cook Time 70 mins Rest Time 5 mins Total Time 1 hr 35 mins

Cooking Temp: 230  C Servings: 5 Estimated Cost: $ 25 Calories: 320

Best Season: Winter, Fall

Description

This homemade French Onion Soup recipe will knock your socks off! Made with the richest broth, perfectly caramelized onions, and topped with three different types of melted cheese, it’s a bistro-worthy comfort dish that’s surprisingly easy to make. Whether it’s a chilly evening or you’re craving something deeply savory, this soup delivers unforgettable flavor in every spoonful.

ingredients

Scale

1/2x 1x 2x 3x

Soup Base

• 4 tablespoons unsalted butter
• 5 large yellow onions (thinly sliced)
• 1 teaspoon salt (for caramelizing)
• 1 teaspoon granulated sugar (to aid caramelization)
• 2 cloves garlic (minced)
• ¹⁄₂ cup dry red wine (such as Cabernet Sauvignon)
• 32 ounces low-sodium beef broth
• 24 ounces low-sodium chicken broth
• 1 tablespoon Worcestershire sauce
• 2 sprigs fresh thyme
• 1 bay leaf
• ¹⁄₂ tablespoon balsamic vinegar
• pinch salt and freshly ground black pepper (to taste)

Cheesy Crouton Topping

• 5 1-inch thick slices French bread
• 2 tablespoons olive oil (for brushing)
• 1.5 cups shredded Gruyere Swiss cheese (room temperature)
• ¹⁄₄ cup shredded Mozzarella cheese (room temperature)
• 2 tablespoons finely grated Parmesan cheese (room temperature)

Instructions

1. Caramelize the onions

   In a large pot over medium-high heat, melt the butter. Add the sliced onions and sauté, stirring often, until softened (about 10 minutes). Reduce heat to medium, stir in salt and sugar. Cook for another 35 minutes, stirring every 5 minutes, until onions are deeply caramelized and syrupy.

2. Add aromatics

   Add minced garlic and cook until fragrant, about 20 seconds.

3. Deglaze

   Pour in the red wine, scraping up any browned bits from the bottom of the pot.

4. Simmer the broth

   Add beef broth, chicken broth, Worcestershire sauce, thyme sprigs, and bay leaf. Gently simmer over medium-low heat for 20 minutes, stirring occasionally.

5. Finish the soup

   Remove and discard thyme sprigs and bay leaf. Stir in balsamic vinegar. Taste and adjust seasoning with salt and pepper as needed. Keep soup warm on low heat while preparing the topping.

6. Toast the bread

   Preheat oven broiler with rack 6 inches from heat. Arrange bread slices on a baking sheet. Brush both sides with olive oil. Broil 2–3 minutes total, flipping once, until golden and crisp. Watch closely to prevent burning.

7. Assemble and broil

   Place 5 oven-safe soup bowls on a rimmed baking sheet. Fill each 2/3 full with hot soup. Top each with a toasted bread slice. Evenly sprinkle with Gruyere, Mozzarella, and Parmesan cheeses.

8. Broil until golden

   Place under the broiler until cheese is bubbly and golden brown (2–4 minutes). Serve immediately.

Nutrition Facts

Servings 5

Serving Size 1 bowl (approx. 1.5 cups soup + topping)

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Amount Per Serving

Calories 320kcal

% Daily Value *

Total Fat 16g25%

Saturated Fat 8g40%

Cholesterol 35mg12%

Sodium 890mg38%

Potassium 520mg15%

Total Carbohydrate 32g11%

Dietary Fiber 3g12%

Sugars 12g

Protein 14g29%

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Calcium 220 mg

Iron 2 mg

* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.

Note

• Make ahead: Soup base (without bread/cheese) can be refrigerated for up to 3 days or frozen for 3 months. Reheat and add fresh topping before serving.
• Wine substitute: Replace red wine with additional beef broth + 1 tsp red wine vinegar if needed.
• Cheese tip: Always shred cheese fresh—pre-shredded contains anti-caking agents that hinder melting.
• Serving suggestion: Pair with a simple green salad or crusty baguette for a complete meal.

Keywords: French onion soup, caramelized onion soup, cheesy onion soup, beef broth soup, classic French recipe