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

If you’ve ever dreamed of making a cozy, comforting soup that feels like a warm hug in a bowl, then this Classic French Onion Soup Recipe is exactly what you need. Rich, caramelized onions swimming in savory broth, topped with golden toasted bread and melted cheese—it’s a showstopper you’ll want to make again and again.

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

French onion soup is one of those classic dishes that feels fancy but is surprisingly easy to make at home. I fell in love with it after my first attempt at caramelizing onions for hours—it’s worth every minute on the stove!

Deep, rich flavor: The slow caramelization of onions releases natural sugars that make the broth so irresistibly savory.
Simple ingredients: With just onions, broth, and a few seasonings, this recipe lets the classic flavors shine through.
Comfort food at its finest: Gooey melted cheese and crusty bread on top make it the ultimate cozy meal.
Customizable: Whether you want to add a splash of sherry or swap cheeses, it’s easy to make this soup your own.

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

What’s elegant about this Classic French Onion Soup Recipe is how few ingredients you need to create such a complex flavor profile. Each one plays its role perfectly.

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 deepens with caramelization; avoid watery or very mild onions.
Olive oil & butter: The combination adds richness and helps the onions brown evenly without burning.
Garlic: Adds subtle depth but shouldn’t overpower the onions.
Beef broth: Choosing a high-quality, flavorful broth is key since it forms the soup’s base.
Dry sherry (optional): Brings a lovely hint of acidity and complexity; you can skip or substitute with white wine if preferred.
Dried thyme: Classic herb that pairs beautifully with onions and beef.
Salt & pepper: Season to taste; these simple seasonings pull all flavors together.
Baguette slices: Toasted to crunchy perfection, they add great texture and soak up that luscious broth.
Gruyère cheese: Melts beautifully with a nutty flavor; you can swap with provolone if easier to find.
Parmesan cheese: Sprinkled on top for a sharp, salty finish that balances the richness.

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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 experimenting with this Classic French Onion Soup Recipe to suit the mood or season. Don’t hesitate to try it with your favorite tweak—it’s flexible!

Variation: I once added a splash of brandy instead of sherry for a warmer, deeper flavor and it was fantastic.
Vegetarian: Swap the beef broth for a rich vegetable broth and boost flavor with a dash of soy sauce or miso paste.
Cheese swaps: If you can’t find Gruyère, Swiss or provolone work just as well for that melty topping.
Make it gluten-free: Use gluten-free baguette or thick slices of gluten-free bread for the topping.

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

Step 1: Caramelize the onions low and slow

This is the heart of your soup. Heat olive oil over medium-high, toss in those sliced yellow onions, and cook until tender—about 5-7 minutes stirring regularly. Then reduce the heat to medium-low and keep cooking, stirring every few minutes, until your onions go from pale to golden and finally deep brown—this can take 15-25 minutes. Patience here = magic!

Step 2: Add the butter and garlic

Once your onions have that gorgeous color, stir in butter and minced garlic. Let it cook another 2 minutes—this step fills your kitchen with irresistible aromas and adds richness to the base.

Step 3: Build the broth and simmer

Pour in beef broth and optional dry sherry, then season with thyme, salt, and pepper. Bring everything to a gentle simmer and let it bubble away for 20 to 30 minutes to marry all those flavors. It’s worth the wait!

Step 4: Toast the bread

Slice your baguette and brush both sides with olive oil. Broil on a baking sheet about 8 inches from the broiler for 2-3 minutes per side until golden brown. Keep an eye on it so it doesn’t burn—bread under the broiler can go from perfect to charcoal quickly.

Step 5: Assemble and broil with cheese

Ladle the hot soup into oven-safe bowls. Lay two toasted baguette slices on top of each bowl, then add a slice of Gruyère and sprinkle grated Parmesan over that. Slide the bowls under the broiler again until the cheese is bubbly and golden—about 2-3 minutes. Serve immediately for that dreamy melty cheese goodness.

Top Tip

From my experience making this Classic French Onion Soup Recipe multiple times, I’ve learned a few key things that make all the difference between good and unforgettable. Let me share them with you!

Take your time with onions: Don’t rush! Slow caramelization brings out the depth and sweetness—this is the soul of your soup.
Watch the bread carefully: Broil the baguette slices close to the heat but keep a close eye—they toast fast and you want crispy, not burnt.
Use oven-safe bowls: This helps when you broil the cheese topping right in the serving dish—safer and easier.
Don’t skip the sherry: While optional, just a splash adds a wonderful brightness that lifts the soup’s richness.

How to Serve Classic French Onion Soup Recipe

Garnishes

I stick with a combo of Gruyère and Parmesan cheese because together they melt perfectly with a deliciously nutty and salty finish. If I'm feeling fancy, I might sprinkle a little fresh thyme on top just before serving for a pop of color and mild herbal note.

Side Dishes

Since this soup is very filling, I usually serve it with light sides like a crisp green salad tossed with vinaigrette or some roasted seasonal veggies. It balances out the richness and makes for a lovely meal.

Creative Ways to Present

For special occasions, I love serving this soup in mini crocks or even small cast iron skillets, giving it that rustic French bistro vibe. A little sprig of fresh thyme or a dusting of paprika on top brings it up a notch and really impresses guests.

Make Ahead and Storage

Storing Leftovers

I cool the soup completely then transfer it to airtight containers for the fridge. It keeps great for up to 4 days—just skip the bread and cheese topping if you plan to store it separately to keep it fresh.

Freezing

This soup freezes surprisingly well. I freeze the broth and onions only (no bread or cheese), and thaw overnight in the fridge before reheating on the stove. When ready to eat, add the bread and melt the cheese fresh under the broiler.

Reheating

Reheat gently on the stovetop until simmering. Then ladle into oven-safe bowls, add fresh toasted baguette and cheese, and broil until bubbly. This way, you get that perfect melty finish every time.

Frequently Asked Questions:

Can I make Classic French Onion Soup Recipe vegetarian?

Absolutely! Swap the beef broth with a high-quality vegetable broth and enhance the savory flavor with a splash of soy sauce or a pinch of mushroom powder.

How long does it take to caramelize onions for this soup?

It typically takes about 20 to 30 minutes over low to medium heat. Patience is essential because slow cooking brings out the onions’ natural sweetness and gives you that deep brown color.

Can I prepare the soup ahead of time?

Yes! You can make the soup base a day ahead and refrigerate it. Just add the bread and cheese topping right before serving to keep them crisp and melty.

What’s the best cheese to use for Classic French Onion Soup Recipe?

Traditionally, Gruyère cheese is preferred for its nutty flavor and excellent melting properties. If you can’t find Gruyère, Swiss, provolone, or even mozzarella are good substitutes.

Final Thoughts

This Classic French Onion Soup Recipe has truly become one of my go-to comfort foods—there’s something utterly satisfying about biting into that crispy bread, oozing with melted cheese and soaking up that flavorful broth. Give yourself the gift of time in the kitchen, and I promise you’ll be rewarded with a bowl full of love. I can’t wait for you to try it and make it your own!