Name: Classic French Onion Soup Recipe
Prep time: 15 min
Cook time: 1 h
Total time: 1 h 15 min
Cuisine: French
Ingredients: 2 tablespoons olive oil; 6 medium yellow onions, sliced; 2 tablespoons butter; 1 tablespoon minced garlic; 8 cups beef broth; 1/4 cup dry sherry (optional); 1 teaspoon dried thyme; 1 teaspoon salt, or to taste; 1/2 teaspoon black pepper, or to taste; 8 slices French baguette; 2 tablespoons olive oil; 4 slices Gruyère cheese or provolone; 2 tablespoons grated Parmesan cheese

Nothing beats the cozy comfort of a warm bowl of soup on a chilly day, and this Classic French Onion Soup Recipe is my absolute favorite for that exact reason. It’s rich, hearty, and topped with ooey-gooey melted cheese that feels like a warm hug. Stick around—I’ll walk you through every step to make it perfect at home.

French Onion Soup - Two white bowls filled with rich brown soup form the base layer, topped with two slices of toasted bread soaked in the soup, golden to light brown and bubbly from melted, browned cheese. The cheese layer has a creamy yellow color mixed with some crisp, darker golden spots. A small sprig of fresh green thyme is placed on top of the cheese for garnish. The bowls sit on a white marbled surface with a few scattered thyme leaves nearby. photo taken with an iphone --ar 2:3 --v 7

Jump to:

Why You'll Love This Recipe
Ingredients & Why They Work
Make It Your Way
Step-by-Step: How I Make Classic French Onion Soup Recipe
Top Tip
How to Serve Classic French Onion Soup Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Classic French Onion Soup Recipe

Why You'll Love This Recipe

I’ve made this Classic French Onion Soup Recipe countless times, and it never fails to impress my family and friends. It’s just one of those dishes that’s deceptively simple yet bursting with deep, layered flavors. If you’ve ever wanted to recreate that iconic French bistro experience at home, you’re in the right place.

Rich Caramelized Onions: Cooking the onions slowly develops a naturally sweet, savory depth you won’t find in shortcuts.
Elegant Simplicity: Just a handful of ingredients work together to create something truly special without fuss.
Cheesy Crust Heaven: The toasted baguette topped with Gruyère and Parmesan is the perfect crunchy, melty contrast.
Flexible and Comforting: Whether it’s a weeknight treat or part of a dinner party, this soup always fits the bill.

French Onion Soup - The image shows a white ceramic bowl filled with dark brown onion soup, topped with a golden-brown melted cheese layer that covers toasted bread slices. A spoon lifts a portion from the bowl, revealing soft cooked caramelized onions with stringy, melted cheese stretching from the soup. There is a green herb sprig on the surface of the soup as garnish. The bowl is placed on a white marbled surface, and there is another similar bowl blurred in the background. Photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

Each ingredient in this recipe plays its own part in building a sensational bowl of soup, and choosing them thoughtfully makes all the difference. I always recommend picking the best quality onions and broth you can find because they’re the heart of this dish.

French Onion Soup - Flat lay of golden sliced yellow onions with their translucent layers shining softly, whole garlic cloves with papery white skins and some minced garlic scattered delicately, glossy sticks of pale butter, fresh sprigs of dried thyme with tiny green leaves, rich dark beef broth in a small glass container catching the light, crusty French baguette slices with a warm golden crust and a textured crumb, smooth pale yellow slices of Gruyère cheese slightly curled at the edges, and fine shreds of snowy white Parmesan cheese sprinkled artistically, all arranged naturally with a balance of colors and textures, placed on white marbled surface, photo taken with an iphone --ar 2:3 --v 7

Yellow Onions: Their natural sweetness intensifies as they slowly caramelize, giving the soup that iconic rich flavor.
Olive Oil & Butter: Olive oil starts the cooking off clean, while butter adds richness and silky texture to the onions.
Garlic: Just a touch to boost the aroma without overpowering the delicate onion base.
Beef Broth: Provides a robust, savory backbone. Don’t skimp here—homemade or good-quality store-bought broth really shines.
Dry Sherry (optional): Adds subtle depth and a mild sweetness; I always include it when I have it on hand.
Dried Thyme: Classic French herb that complements the onions perfectly.
Salt & Pepper: To season and balance all those layered flavors.
French Baguette: Toasted for crunch and structural support for all that cheese and soup.
Gruyère Cheese: The meltiest, nuttiest topping that makes this soup shine.
Parmesan Cheese: Adds a sharp contrast and savory kick when sprinkled on top.

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Note: You'll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Make It Your Way

I love making this Classic French Onion Soup Recipe my own depending on the occasion. Sometimes I jazz it up with a splash of dry white wine instead of sherry or swap in provolone cheese when I’m feeling casual. You can totally tailor it to suit your taste, so don’t be afraid to experiment a little!

Variation: Once, I added a pinch of smoked paprika for a subtle smoky undertone—delicious and unexpected.
Vegetarian Twist: Use vegetable broth to keep it plant-based and still flavorful.
Herbs: Fresh thyme makes a lovely garnish if you want a brighter herbal note right before serving.
Cheese Swap: Gruyère is traditional, but a good quality Swiss or even mozzarella can work if that’s what you have on hand.

Step-by-Step: How I Make Classic French Onion Soup Recipe

Step 1: The Key to Perfect Caramelized Onions

Start by heating olive oil in a large pot over medium-high heat. Add the sliced onions and cook them gently until they soften—about 5 to 7 minutes—stirring occasionally so nothing sticks or burns. Then, lower the heat to medium-low and let the magic happen. This is the most important step—you’ll want to stir every 3 to 5 minutes and be patient as the onions slowly turn deep golden brown. This takes anywhere from 15 to 25 minutes, and it’s worth every second because that caramelized sweetness is the foundation of your soup.

Step 2: Building Layers of Flavor

Once your onions are beautifully caramelized, stir in the butter and minced garlic. Cook for another 2 minutes until the garlic is fragrant and the butter melts fully into the onions, adding a rich silkiness. This small addition brings warmth to the overall flavor.

Step 3: Simmering the Soup

Pour in the beef broth along with the optional dry sherry if you’re using it—trust me, it adds a lovely dimension. Season with dried thyme, salt, and pepper. Bring everything to a simmer on medium-low heat and let it bubble gently for 20 to 30 minutes. This lets the flavors meld and deepen beautifully.

Step 4: Toasting the Baguette

While the soup simmers, get your broiler ready. Brush both sides of your baguette slices with olive oil and broil them on a baking sheet for 2 to 3 minutes per side, watching closely so they turn golden and crisp without burning. Toasting the bread ahead keeps it from becoming soggy too quickly in the soup.

Step 5: Assembling and Broiling

Ladle the hot soup into oven-safe bowls set on a baking sheet. Top each with two toasted baguette slices, then layer on a slice of Gruyère cheese and sprinkle with Parmesan. Pop the whole baking sheet under the broiler for 2 to 3 minutes until the cheese melts, bubbles, and just starts to brown. Keep an eye on it — broiler strengths vary, and you want that perfect golden crust.

Step 6: Serve While It's Bubbling Hot

Enjoy your soup immediately, while the cheese is gooey and melty. This recipe is all about textures and warmth, so don’t let it sit too long.

Top Tip

Over the years, I’ve learned these tips really help nail the Classic French Onion Soup Recipe every time. Caramelizing onions is slow but worth it, and broiling cheese to bubbly perfection is an absolute must.

Low and Slow Caramelizing: Don’t rush the onions! The sweet, complex flavor comes from patience and gentle heat.
Use a Heavy-Bottomed Pot: It helps distribute heat evenly and prevents scorching.
Bread Toasting Matters: Toast your baguette slices twice to keep them crisp under the soup and cheese.
Watch the Broiler: Cheese goes from perfectly melted to burnt quickly—stay close and check often.

How to Serve Classic French Onion Soup Recipe

Garnishes

I usually keep things simple with this soup—just the toasted baguette and cheese top, which is totally classic. But if I’m feeling fancy, a small sprig of fresh thyme on top adds a beautiful touch and a hint of freshness that cuts through the richness.

Side Dishes

Pair this soup with a crisp green salad dressed simply with lemon vinaigrette or some crusty artisan bread on the side for dipping. It also goes wonderfully with roasted vegetables or a light charcuterie platter for a fuller meal.

Creative Ways to Present

For dinner parties, I like serving the soup in individual oven-safe crocks or mini cast iron pots—makes it feel extra special. You can also sprinkle a pinch of smoked sea salt over the cheese just before broiling for a surprising twist.

Make Ahead and Storage

Storing Leftovers

I store leftover soup in an airtight container in the fridge for up to 3 days. The flavors actually deepen overnight, making for even better soup the next day.

Freezing

This Classic French Onion Soup Recipe freezes beautifully. I freeze it without the bread and cheese toppings to avoid sogginess. When you’re ready, thaw it in the fridge overnight and reheat gently on the stove.

Reheating

Reheat leftover soup in a pot over low heat, stirring occasionally. You can re-toast baguette slices and broil cheese fresh on top to recreate that delightful crust each time.

Frequently Asked Questions:

Can I make French onion soup vegetarian?

Absolutely! Just swap the beef broth for a rich vegetable broth, and skip any meat-based seasonings. The onions and cheese alone provide plenty of flavor.

What type of cheese is best for French onion soup?

Gruyère is classic because it melts beautifully and adds a nutty flavor, but you can substitute Swiss or provolone if you want something milder. Parmesan on top adds a nice salty kick.

How long does it take to caramelize onions properly?

It generally takes 20 to 30 minutes on a low heat to develop that deep golden color and sweet flavor. Rushing this step will result in less tasty onions, so slow and steady wins the race.

Can I prepare this soup in advance?

Yes! You can make the soup up to 2 days ahead, then reheat it and add the toasted bread and cheese topping fresh before serving for the best texture.

Final Thoughts

This Classic French Onion Soup Recipe is one of those treasured dishes I always come back to when I want something soul-warming and satisfying. It’s a happy mix of tradition and comfort that’s easier to make than you might think. Give it a try—you’ll be amazed how a few humble ingredients can create such magic in a bowl. Grab your apron, and let’s get cooking!