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 truly comforting about a warm bowl of rich, caramelized onions swimming in a savory broth topped with melty cheese—that’s the magic of this Classic French Onion Soup Recipe. It’s a timeless dish that invites you in with its deep flavors and cozy vibes.

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 remember the first time I made this Classic French Onion Soup Recipe at home—it filled the kitchen with that intoxicating aroma of caramelized onions and melted Gruyère that instantly lifted my spirits. It’s more than just soup; it feels like a little celebration of simple ingredients done right.

Deeply flavorful: Caramelizing the onions slowly brings out a natural sweetness that turns this soup into a comforting masterpiece.
Simple ingredients: You only need a handful of pantry staples and some basic technique to create a restaurant-worthy dish.
Perfect for cozy nights: This soup warms you up from the inside out, making it ideal for chilly evenings or as a welcoming starter for dinner guests.
Customizable & fun to serve: From toasty baguette slices to bubbling cheese, you get to play chef and create a decadent finish that’s all your own.

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

Each ingredient in this Classic French Onion Soup Recipe plays a crucial role in crafting that perfect balance of flavors and textures. Choosing quality onions and broth really pays off, and a touch of sherry adds that subtle complexity that lifts the whole bowl.

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: These bring a natural sweetness that deepens beautifully when caramelized—patience here is key!
Olive oil: Used to gently start the onion cooking process without overpowering their flavor.
Butter: Adds richness and helps carry the garlic’s aroma deeply into the soup.
Minced garlic: Just a subtle punch that wakes up the broth and onion combo.
Beef broth: The backbone of this soup, choose low-sodium for better control over salt.
Dry sherry (optional): A splash enhances depth and aroma—totally worth having on hand.
Dried thyme: An herbaceous note that complements the sweetness and savory elements perfectly.
Salt & pepper: To season just right, adjust according to your broth’s saltiness.
French baguette: Crisped to golden perfection to hold up under the bubbly cheese topping.
Gruyère cheese: Melts beautifully with a nutty and creamy flavor that’s classic to this dish.
Parmesan cheese: Adds a sharp, salty finish that rounds out the cheesy goodness.

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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 just the way it's written, but I’m always tweaking little things depending on the season or what I have on hand. It’s such a versatile recipe that’s perfect for playing around with flavors or dietary preferences.

Variation: Sometimes I swap the beef broth for a rich vegetable broth when I want a lighter or vegetarian-friendly option. It works surprisingly well and still gives that comforting feel.
Cheese swap: Gruyère is classic, but I’ve used provolone or even a blend of mozzarella and Parmesan when I’m craving a different cheese profile.
Extra herbs: Occasionally, I toss in fresh thyme or rosemary sprigs while simmering for an herbal punch.
Gluten-free: Use gluten-free bread for topping and double-check your broth ingredients to keep it friendly for gluten sensitivities.

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

Step 1: Patience is key – caramelize the onions slowly

Start heating 2 tablespoons of olive oil over medium-high heat and add your sliced yellow onions. Stir occasionally so they soften evenly—this takes about 5 to 7 minutes at first. Then reduce to medium-low and let them work their magic, stirring every few minutes for about 15 to 25 minutes until they’re a gorgeous golden brown. Resist the urge to rush; this step is what builds the deep flavor foundation for your soup.

Step 2: Add butter and garlic for richness and aroma

Stir in 2 tablespoons of butter and the minced garlic, cooking just about 2 minutes until everything smells heavenly and the butter melts into the onions. This step enhances the overall richness, giving the soup that silky mouthfeel.

Step 3: Build your broth and simmer

Pour in 8 cups of beef broth and, if you’re using it, ¼ cup dry sherry for that extra layer of flavor. Season with dried thyme, salt, and pepper. Bring it all up to a gentle simmer, then lower the heat to keep it just barely bubbling. Let it simmer uncovered for 20 to 30 minutes to let the flavors blend beautifully.

Step 4: Prepare your toasty baguette rounds

While your soup simmers, preheat the broiler and brush both sides of your baguette slices with olive oil. Pop them under the broiler for 2 to 3 minutes on each side until they turn golden and crispy. Keep an eye on them—broilers can be tricky and you don’t want burnt bread! These will provide the perfect crunchy, cheesy topping.

Step 5: Assemble and broil till bubbly

Ladle the hot soup into oven-safe bowls set on a baking sheet. Place two toasted baguette slices on top of each, then layer with a slice of Gruyère and a sprinkle of Parmesan. Broil just until the cheese bubbles and starts to turn golden brown—about 2 to 3 minutes. This final browning step is what makes it irresistibly good.

Top Tip

From my experience, French onion soup shines when you pay attention to a few crucial details that aren’t obvious at first glance. These tips helped me elevate my soup from just okay to something restaurant quality.

Slow Caramelization: Don’t rush your onions—slow cooking lets their natural sugars develop fully and creates that signature deep flavor.
Watch the Broiler: Broiling can change in seconds, so keep a close eye to prevent burning your cheesy topping.
Use Oven-Safe Bowls: Make sure your bowls handle the broiler heat or else you risk breaks or spills.
Adjust Salt Last: Your broth may already contain salt, so season gradually and taste at the end to avoid oversalting.

How to Serve Classic French Onion Soup Recipe

Garnishes

I usually keep my garnishes simple with just the toasted baguette slices and melty Gruyère layered on top because that combo is so luxurious on its own. Occasionally, I toss a sprinkle of fresh thyme leaves on top for a pop of color and freshness right before serving.

Side Dishes

A crisp green salad with a tangy vinaigrette cuts through the richness of the soup perfectly. I also like pairing it with roasted vegetables or a light crusty bread if you want a bit more to nibble on alongside your soup.

Creative Ways to Present

For special occasions, I’ve served this Classic French Onion Soup Recipe in individual mini cast iron pots or rustic crocks—turns it into a charming centerpiece. Another fun trick is to swirl in a drizzle of truffle oil just before serving for an extra touch of elegance.

Make Ahead and Storage

Storing Leftovers

Leftover soup stores well in an airtight container in the fridge for up to 3 days. I recommend keeping the bread and cheese separate and adding them fresh when reheating to preserve their texture.

Freezing

I've frozen this soup without the bread and cheese with good results—just cool completely and store in freezer-safe containers for up to 3 months. Thaw overnight in the fridge before reheating on the stove.

Reheating

Reheat gently on the stovetop over low heat, stirring occasionally. Add the toasted baguette and cheese after warming the soup, then broil briefly just before serving to get that freshly bubbly top again.

Frequently Asked Questions:

Can I make Classic French Onion Soup Recipe vegetarian?

Yes! Substitute the beef broth with a rich vegetable broth and skip the sherry if desired. This variation still captures the rich, caramelized onion flavors beautifully.

What’s the best cheese for French onion soup?

Gruyère is the traditional choice because of its excellent melting properties and nutty flavor, but Swiss, provolone, or even mozzarella mixed with Parmesan can be fantastic alternatives depending on your preference.

How long does it take to caramelize onions properly?

Caramelizing onions well takes patience—usually about 20 to 30 minutes over medium-low heat—to bring out their natural sweetness and avoid burning. Stir occasionally and watch the color carefully.

Can I prepare this soup ahead of time?

Absolutely! The soup base can be made a day or two in advance and stored in the refrigerator. Toast the bread and add cheese just before serving for the best texture and flavor.

Final Thoughts

This Classic French Onion Soup Recipe is genuinely one of those dishes that feels like a warm hug, perfect for slowing down and savoring every spoonful. Whether you make it for yourself on a quiet evening or to impress friends at a dinner party, it’s reliably delicious. I hope you give this recipe a try—it’s become a comforting staple in my kitchen, and I’m confident you’ll enjoy it just as much.