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 nothing quite like the rich, comforting flavors of a Classic French Onion Soup Recipe to warm you up on a chilly day. This timeless dish combines caramelized onions, savory broth, and bubbling melted cheese on toasted baguette slices—let me walk you through how to make it perfectly every time.

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

This Classic French Onion Soup Recipe holds a special place in my heart—not only because it tastes like pure comfort but also because it’s surprisingly straightforward. With a few pantry staples and a bit of patience, you get that deep caramelized onion flavor that’s so hard to beat.

Deep, rich flavor: Slowly caramelizing the onions brings out natural sweetness that’s pure gold in every spoonful.
Cheesy, toasty topping: The gratinéed Gruyère on baguette slices adds that irresistible melty, crusty finish.
Flexible to customize: Whether you want to add a splash of sherry or swap cheeses, this soup adapts beautifully to your taste.
Perfect for cozy nights: It’s great as a starter or a meal on its own— you'll find yourself reaching for this soup again and again.

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

This recipe calls for a simple list of quality ingredients that come together for an unforgettable soup. Using yellow onions gives you a perfect balance of sweetness and savory depth, while beef broth adds that hearty umami base. Here's a quick breakdown of what you'll use and why each ingredient matters.

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 sugars caramelize beautifully, creating the base flavor.
Olive oil: Helps soften onions without overpowering their flavor.
Butter: Adds richness and helps develop the luscious texture.
Garlic: Provides a subtle aromatic boost without stealing the spotlight.
Beef broth: Offers a deep savory background classic to French onion soup.
Dry sherry (optional): Adds subtle nuttiness and complexity—feel free to skip if you prefer.
Dried thyme: Layer of herbal note that lifts the soup.
Salt and black pepper: Essential seasonings to balance flavors.
French baguette slices: Toasted for that crispy base of the cheesy topping.
Gruyère cheese: Melted perfectly over the bread, it’s what makes the soup truly indulgent.
Parmesan cheese: Adds a bit of sharpness and extra flavor depth.

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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 parts about this Classic French Onion Soup Recipe is how you can easily tweak it to your liking. Over time, I’ve tried swapping out ingredients depending on what I have on hand or dietary preferences, and it still turns out incredible every time.

Variation: For a vegetarian twist, use vegetable broth instead of beef broth. I tried this once when cooking for friends who don’t eat meat, and it was just as flavorful, especially with extra thyme and a splash of soy sauce for umami.
Cheese swap: If you don’t have Gruyère, provolone or even Swiss cheese work nicely, adding their own unique meltiness.
Wine substitute: When I run out of dry sherry, a dry white wine or even a little apple cider vinegar adds a subtle complexity.

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

Step 1: Get Those Onions Perfectly Caramelized

Start by heating the olive oil in a large pot over medium-high heat, then add your thinly sliced yellow onions. Stir occasionally as they soften, about 5–7 minutes. Then reduce the heat to medium-low and stir every few minutes, letting those onions slowly transform into a rich, golden-brown caramelized dream—it usually takes about 15 to 25 minutes. The key is patience here; rushing this step means missing out on that signature sweetness. If the onions start sticking, you can add a splash of water to loosen the fond on the pan bottom.

Step 2: Add Butter and Garlic for Extra Flavor

Once your onions are perfectly caramelized, stir in the butter and minced garlic. Cook for just a couple of minutes until the butter melts and the garlic releases its aroma—be careful not to burn the garlic or you'll get a bitter note. This step adds that rich, inviting base you want in your soup.

Step 3: Pour in Broth, Sherry, and Seasonings

Next, add your beef broth and the optional dry sherry. Sprinkle in thyme, salt, and pepper. Bring everything to a simmer, then reduce heat and let it gently bubble for 20 to 30 minutes. This simmers the flavors together perfectly and gives the soup a comforting, warm depth. I’ve learned that too high a heat can dull the flavors, so keep it gentle here.

Step 4: Toast Your Baguette Slices

While the soup simmers, preheat your oven’s broiler. Brush both sides of the baguette slices with olive oil and toast them on a baking sheet under the broiler for 2 to 3 minutes per side until golden brown. Watch these like a hawk—they’ll go from perfect to burnt in seconds if you’re not careful. These toasty slices will become the perfect base for your cheese topping.

Step 5: Assemble and Broil for That Classic Cheese Melt

Ladle your soup into oven-safe bowls set on a baking sheet. Lay two toasted baguette slices on top of each bowl, then pile on a slice of Gruyère and sprinkle grated Parmesan over it. Pop the whole tray under the broiler until the cheese bubbles and gets those irresistible golden brown spots, typically 2 to 3 minutes. Keep a close eye—cheese can go from bubbling to burnt fast! This final step is what turns simple soup into the luxurious classic you know and love.

Top Tip

After making Classic French Onion Soup Recipe dozens of times, a few tricks have made all the difference between "just good" and "unforgettable." Here's what I always keep in mind.

Patience is your friend: Take your time caramelizing onions; rushing this stage is the biggest mistake I see.
Low and slow simmers: Keep the soup at a gentle simmer when it’s cooking to help flavors marry without evaporating too much liquid.
Broiler watch: When melting cheese on soup bowls, always stay close by—broilers can be wildly powerful depending on your oven.
Use good broth: A quality beef broth makes all the difference; homemade or a trusted store-bought brand will elevate your soup.

How to Serve Classic French Onion Soup Recipe

Garnishes

I love adding a sprinkle of freshly chopped parsley or thyme leaves right before serving—it adds a fresh, herbal brightness that balances the richness. Sometimes, a tiny drizzle of truffle oil elevates the experience when I’m feeling fancy, but it’s totally optional.

Side Dishes

This soup shines on its own, but if you want to round out your meal, I like pairing it with a crisp green salad tossed with a simple vinaigrette or some roasted vegetables. A light baguette with butter alongside is perfect for soaking up every last drop.

Creative Ways to Present

For a special occasion, try serving the soup in individual mini cast iron skillets or charming crocks—everyone loves the personal touch. You can also experiment with layering the toasted bread and cheese multiple times for extra indulgence, turning it into a French onion soup "lasagna" style!

Make Ahead and Storage

Storing Leftovers

I usually store leftover soup (without the bread or cheese) in an airtight container in the fridge for up to 3 days. Keep everything cool and sealed to preserve that deep onion flavor.

Freezing

Classic French Onion Soup Recipe freezes surprisingly well. Just freeze the soup base in portions without the bread and cheese to avoid sogginess. When thawed, reheat gently and then freshly toast baguette slices and melt cheese just before serving.

Reheating

To reheat, warm the soup gently on the stove over low-medium heat, stirring occasionally. Then, assemble your toasted bread and cheese topping right before serving for the best texture and flavor.

Frequently Asked Questions:

Can I use other types of onions for French onion soup?

Yellow onions are my favorite because they caramelize well and have the perfect balance of sweetness and depth. However, you can also use sweet onions or a mix of onions if you prefer. Just keep in mind that some onions have more water content, which may affect cooking time.

Is dry sherry necessary in this recipe?

Dry sherry is optional but adds a lovely nutty and complex flavor to the soup. If you don’t have it or prefer not to use alcohol, you can skip it or substitute with a splash of dry white wine or apple cider vinegar for a bit of acidity.

Why should I use Gruyère cheese?

Gruyère melts beautifully and has a creamy, slightly nutty flavor that pairs perfectly with caramelized onions and beef broth. It’s the classic cheese for French onion soup, but if you can’t find it, provolone or Swiss cheese are great alternatives.

Can I make this soup ahead of time?

Absolutely! You can make the soup base a day or two ahead and store it in the fridge. Just add the toasted baguette and cheese topping right before serving to keep everything crispy and melty.

Final Thoughts

Making this Classic French Onion Soup Recipe feels like a little act of self-care, filling your kitchen with incredible aromas and delivering comfort in every bite. Whether it’s a quiet night in or you’re sharing with friends, this soup is a crowd-pleaser that never disappoints. I can’t wait for you to try it—you’re going to love how simple ingredients transform into something extraordinary.