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

There’s something irresistibly cozy and rich about a bowl of perfectly caramelized onions swimming in a savory broth, topped with gooey melted cheese. That’s exactly what makes this Classic French Onion Soup Recipe so special and absolutely worth making from scratch in your own kitchen.

This image shows two white mugs with handles filled with French onion soup. Each mug has a dark brown onion broth as the bottom layer. On top of the broth are two toasted brown bread slices covered by melted golden cheese that is bubbly and slightly browned. A small green herb branch sits on top of the cheese in each mug, adding a fresh touch. The mugs are placed on a white marbled surface with some small scattered herb leaves around. The scene has a cozy and warm feeling. 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 tried a few French onion soup recipes over the years, but this Classic French Onion Soup Recipe truly hits that balance between simplicity and deep, comforting flavor that keeps me coming back. It’s easy enough for a weeknight but indulgent enough for guests.

Intense Caramelization: Slow cooking the onions brings out their natural sweetness, making every spoonful rich and flavorful.
Homemade Broth Base: Using beef broth with a splash of dry sherry adds savory depth without a ton of fuss.
Crispy, Cheesy Topping: Toasted baguette slices topped with Gruyère and Parmesan melt perfectly under the broiler.
Comfort Food Classic: This recipe warms you up on chilly days and impresses without requiring fancy ingredients.

The image shows a white bowl filled with golden brown French onion soup topped with melted cheese that looks bubbly and slightly crispy. On top of the cheese, there is a layer of caramelized onions that are light golden and shiny. A spoon is lifting a portion of the cheese and onions from the bowl, showing the texture of the melted cheese stretching and the soft onions underneath. There is another white bowl with the same soup blurred in the background. The bowls sit on a white marbled surface, giving a clean and bright look. A small green herb garnish is placed on top of the soup, adding a touch of color photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

This recipe revolves around simple, honest ingredients that combine into something magical. Each plays a key role in building the soup’s signature layers of flavor, so choose quality where you can—especially the broth and cheese.

Flat lay of a medium pile of thinly sliced yellow onions, a small pool of golden olive oil in a shallow dish, a few pats of soft butter on a wooden board, a small bowl with minced garlic, a large bowl filled with rich dark beef broth, a small glass with amber dry sherry, a tiny heap of dried thyme, scattered coarse salt and black peppercorns, several slices of crusty French baguette brushed with olive oil, thin slices of Gruyère cheese, and a small mound of grated Parmesan cheese placed on a white marble surface, photo taken with an iphone --ar 2:3 --v 7

Yellow onions: Their balance of sweetness and sharpness softens beautifully as they caramelize, forming the soup’s base.
Olive oil & butter: The olive oil helps start the cooking, while butter adds richness and helps brown the onions evenly.
Minced garlic: Adds a gentle aromatic kick without overpowering the sweetness of the onions.
Beef broth: A hearty, meaty backbone that infuses depth—homemade or good quality store-bought both work.
Dry sherry (optional): I like to add this for a subtle complexity—it lifts the broth with a little tangy warmth.
Dried thyme: A classic herb that pairs perfectly with caramelized onions by adding earthiness.
Salt & black pepper: Essential seasonings to enhance and balance all the flavors.
French baguette: Toasted slices provide the necessary crunch and structure to hold the gooey cheese topping.
Gruyère cheese: Its nutty, melty quality is perfect for that luscious browned crust.
Parmesan cheese: Adds a sharp bite and savory finish to the cheese topping.

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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

One of my favorite things about this Classic French Onion Soup Recipe is how easy it is to make your own. I love swapping cheese or playing with the broth base depending on what’s in my fridge.

Variation: I sometimes use a blend of Gruyère and smoked provolone for a slightly smoky twist that adds more depth.
Vegetarian Twist: Sub a rich vegetable broth for the beef broth, and add a splash of soy sauce to deepen umami flavor.
Seasonal Boost: Toss in a few fresh thyme sprigs or a bay leaf during simmering to add freshness.

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

Step 1: Slowly Caramelize the Onions

Start by heating olive oil in a large pot over medium-high heat, then add your sliced onions. Stir occasionally for the first 5 to 7 minutes until they soften. Then turn the heat down to medium-low and keep stirring every few minutes for about 15 to 25 minutes until the onions turn a deep golden brown. Patience here pays off big time—the slow caramelization is where all that sweet, rich flavor develops. If they start to stick, add a splash of water or broth to loosen the pan without burning.

Step 2: Add Garlic and Butter

Once the onions are beautifully caramelized, stir in butter and minced garlic until the butter melts and the garlic becomes fragrant—just a couple of minutes. This step adds richness and a nice aromatic note that complements the onions perfectly.

Step 3: Build the Broth

Pour in your beef broth and optional dry sherry, sprinkle in thyme, salt, and pepper, then bring everything to a gentle simmer. Turn the heat low and let it simmer for 20 to 30 minutes to allow all those flavors to marry. It’s an easy step but crucial for that deep, soulful taste.

Step 4: Prepare the Toasted Baguette Slices

While your soup simmers, preheat your oven’s broiler and position the rack about 8 inches from the heat source. Brush both sides of baguette slices with olive oil and arrange them on a baking sheet. Broil for 2 to 3 minutes per side, keeping an eagle eye to avoid burning. The goal is perfectly crisp, golden toasts that will soak up the soup but still hold their shape under the cheese.

Step 5: Assemble and Broil

Ladle your soup into oven-safe bowls placed on a baking sheet. Top each bowl with two toasted baguette slices, then layer on slices of Gruyère and sprinkle grated Parmesan over the top. Place the baking sheet under the broiler for 2 to 3 minutes until the cheese bubbles and browns lightly. Don’t walk away—the broiler can move quickly here!

Top Tip

After making this Classic French Onion Soup Recipe multiple times, a few tips helped me get consistent delicious results. These small details make a big difference in flavor and texture.

Low & Slow Onion Cooking: Resist the urge to rush caramelization with high heat—you’ll get bitter edges. Slow cooking brings out natural sugars perfectly.
Watch the Broiler: Broilers vary, so keep a close eye when browning the cheese to avoid burning, which happens faster than you expect.
Bread Thickness: I slice baguette about ½ inch thick to get toast that’s sturdy yet still sinks slightly into the soup.
Flavor Boosters: If you want a touch more depth, a splash of dry sherry or a pinch of smoked paprika can elevate the broth wonderfully.

How to Serve Classic French Onion Soup Recipe

Garnishes

I usually keep garnishes simple for this soup—just a sprinkle of fresh thyme or a few cracked black peppercorns on top after broiling. It adds a fresh pop of aroma and color without competing with the rich cheese topping.

Side Dishes

This soup is a meal on its own, but I love pairing it with a crisp green salad dressed lightly in a lemon vinaigrette or a simple roasted vegetable side to balance the richness. A fresh baguette on the side never hurts either!

Creative Ways to Present

For special occasions, I serve this soup in mini crock bowls or French onion soup mugs, perfect for individual servings. You can also add a sprinkle of fresh herbs or a dash of truffle oil on the cheese topping to wow your guests.

Make Ahead and Storage

Storing Leftovers

I store leftover soup in airtight containers in the fridge for up to 3 days. The bread and cheese topping don’t keep well, so I store the soup and toast separately to maintain texture and freshness for later.

Freezing

This soup freezes beautifully without the bread and cheese. Just cool the broth completely, then freeze in portioned containers. Defrost overnight in the fridge and reheat gently on the stove before adding fresh toasted bread and cheese.

Reheating

I recommend reheating the soup on the stovetop over medium heat until warmed through, then broiling freshly toasted baguette slices with cheese as you did initially. This keeps the dreamy textures intact.

Frequently Asked Questions:

Can I make this Classic French Onion Soup Recipe vegetarian?

Absolutely! Swap the beef broth for a rich vegetable broth and add a splash of soy sauce or tamari to deepen the umami flavor. Skip the dry sherry or substitute with a vegetarian-friendly alternative. The soup will still be deliciously comforting.

What’s the best cheese for French onion soup?

Gruyère is classic for its nutty, melting qualities, but you can also use Emmental, Swiss cheese, or provolone. Avoid cheeses that don’t melt well to get that beautiful bubbly, golden crust.

How do I avoid the onions from burning while caramelizing?

The key is to keep the heat medium-low once the onions soften and to stir every few minutes. If they start sticking, add a splash of water or broth to deglaze the pan and prevent burning. Patience is essential for sweet, golden-brown onions.

Can I prepare the soup in advance?

Yes! The soup base can be made a day or two ahead and refrigerated. Reheat gently on the stove before adding the toasted bread and melt the cheese just before serving for best texture and flavor.

Final Thoughts

This Classic French Onion Soup Recipe is a beloved favorite in my kitchen because it’s both humble and luxurious at the same time—a bowl of comfort that doesn’t require complicated steps or ingredients. I hope you enjoy making and savoring it as much as I do, whether for weeknight dinners or special gatherings. Trust me, once you’ve tasted that melty cheesy crust atop the rich onion broth, you’ll be hooked for life!