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 craved that rich, caramelized onion goodness bubbling under a golden cheesy crust, you’re going to love this Classic French Onion Soup Recipe. It’s comfort in a bowl, easy enough to make on a weeknight but special enough to impress anyone at your table. Stick around, and I’ll walk you through every delicious step.

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 has this magical way of feeling both cozy and elegant. I’ve made this classic recipe countless times—sometimes on a chilly evening with just myself, other times as a show-stopper when friends come over. Each time, the caramelized onions and fragrant broth deliver that unmistakable, soul-warming flavor that never disappoints.

Deep, rich flavor: Long, slow caramelization of onions builds the soup’s legendary sweetness and complexity.
Simple ingredients, big impact: With pantry staples like onions, broth, and a few cheeses, you get an authentic, refined taste.
Perfect cheesy crust: Toasted baguette slices topped with bubbling Gruyère and Parmesan make this soup unforgettable.
Comfort food at its best: Whether for a weeknight or a cozy dinner date, this recipe warms your heart and tummy.

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 soup shines because the ingredients really sing together. Onions get caramelized slowly, bringing out their natural sweetness, while the beef broth adds deep, savory notes. A splash of dry sherry gives it a gentle lift, and the cheese topping finishes things off with melty magic. When shopping, fresh yellow onions and a good-quality broth make all the difference.

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 and sturdy texture make them ideal for caramelizing slowly to golden perfection.
Olive oil and butter: Using both fat types enhances richness and helps develop that luscious caramelized flavor.
Garlic: Just a bit adds warmth and fragrant depth without overpowering the onions.
Beef broth: The backbone of the soup—choose a good-quality or homemade version for best results.
Dry sherry (optional): Adds complexity and a subtle tang, though you can skip it if you prefer.
Dried thyme: Brings an earthy herbal note that complements the beef and onions beautifully.
French baguette: Toasted to golden crispness, it holds up under the cheese and soup.
Gruyère cheese: Classic for a reason—melts beautifully with an irresistible nutty flavor.
Parmesan cheese: Adds sharpness and extra umami layered 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 like to play around a bit with this Classic French Onion Soup Recipe depending on what I have on hand or the mood I'm in. It’s a great base to personalize! Don’t hesitate to tweak the cheese, experiment with herbs, or add your own twist to the broth.

Variation: Sometimes I swap the Gruyère with a sharp provolone or fontina for a different melty texture and flavor, which works just as wonderfully.
Vegetarian option: Use vegetable broth instead of beef broth and skip the sherry for a lighter, meat-free version that still tastes rich.
Add a splash of wine: Red or white wine instead of sherry can add an interesting complexity if you want to experiment.
Make it heartier: Toss in a few mushrooms along with the onions for extra depth and an earthy aroma.

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

Step 1: Slow and steady caramelizing is key

Heating olive oil in a large pot, I start by softening the sliced onions over medium-high heat just until they’re tender. Then, I drop the heat to medium-low and take my time, stirring every few minutes. This part can take 20-30 minutes to get those onions a deep golden caramel color. It’s tempting to rush, but trust me, this slow caramelization makes the soup irresistible. Watch the onions closely to avoid burning, stirring gently when the edges start browning.

Step 2: Adding butter and garlic

Once the onions have reached that rich caramel state, I stir in the butter with the garlic, cooking just a couple of minutes until the garlic smells wonderful. This step adds lush creaminess that balances the sweetness and layers on aromatics for that classic flavor.

Step 3: Simmering with broth and herbs

I pour in the beef broth, a splash of dry sherry if I have it, then season with thyme, salt, and pepper. Bringing it to a gentle simmer, I let the flavors meld for about 20-30 minutes. This reduces a bit and becomes wonderfully savory — simmering gently avoids a harsh boil that can muddy flavors.

Step 4: Preparing the golden toasts

While the soup bubbles away, I preheat my broiler and get the baguette slices ready, brushing them well with olive oil on both sides. Then under the broiler they go for a quick 2-3 minutes per side until beautifully toasted and golden. It’s worth standing by the oven here—bread can flash from perfect to burnt in seconds!

Step 5: Cheese, broiling, and serving

I ladle the hot soup into oven-safe bowls, top with two slices of my crunchy baguette, then layer on Gruyère and a sprinkle of Parmesan. Sliding those bowls under the broiler for just a couple minutes melts the cheese into a bubbly, aromatic crown. Keep a close eye since broilers vary—you want golden, not burnt. Serve immediately and enjoy the cozy, melty magic!

Top Tip

Having made this recipe more times than I can count, I’ve learned a few tricks that take the soup from good to unforgettable:

Patience in caramelizing: Resist the urge to crank up the heat or rush stirring. Low and slow creates deep, sweet flavors that define this soup.
Watch the broiler: When it’s cheese time, broilers can be hot and fast—stay near the oven to avoid scorched cheese.
Use oven-safe bowls: This prevents dish disasters and helps the cheese melt evenly under the broiler.
Don’t skip the toast oiling: Brushing the baguette slices with olive oil before toasting creates that perfect crisp crust and prevents soggy bread in your soup.

How to Serve Classic French Onion Soup Recipe

Garnishes

I keep it classic here: a generous sprinkle of freshly grated Parmesan on top of bubbling Gruyère. Sometimes I add a few fresh thyme leaves for color and that lovely herbal punch. Nothing beats the gooey cheese melting into the broth and soaking into the baguette!

Side Dishes

This soup is a star on its own but pairs nicely with light sides to round out the meal—think a crisp green salad with a lemon vinaigrette or simply some roasted vegetables. When I’m feeling indulgent, a glass of Burgundy always elevates the whole experience.

Creative Ways to Present

For dinner parties, I love serving the soup in mini cast iron crocks or ramekins placed on a rustic wooden board. A tiny herb sprig on top adds a fresh pop. Alternately, lining up little crostinis alongside the bowls invites guests to customize their bites. It’s simple but makes the meal feel extra special.

Make Ahead and Storage

Storing Leftovers

Leftover French onion soup keeps beautifully in an airtight container in the fridge for up to 3 days. I recommend storing the soup separately from the bread and cheese to keep textures fresh. When you’re ready to eat, just heat the soup gently on the stovetop.

Freezing

Yes, you can freeze this soup! I freeze the broth and onions without the bread or cheese in freezer-safe containers for up to 3 months. When thawed, I toast fresh baguette slices and add cheese before broiling to keep flavors bright and textures perfect.

Reheating

Reheat leftovers slowly on the stove over low heat to prevent drying out or bitterness. If you want the cheesy topping again, ladle soup into oven-safe bowls, add fresh toasted baguette and cheese, then broil briefly just before serving.

Frequently Asked Questions:

Can I make French onion soup without beef broth?

Absolutely! You can substitute vegetable broth for a vegetarian version. Just keep in mind the flavor will be lighter, but caramelized onions and herbs still make it delicious.

Is dry sherry necessary in this Classic French Onion Soup Recipe?

Dry sherry adds an amazing depth of flavor, but it’s optional. If you don’t have any or prefer not to use alcohol, simply skip it or replace with a splash of white wine or even a bit of apple cider vinegar for brightness.

How do I prevent the onions from burning while caramelizing?

Cook the onions slowly over medium-low heat, stirring every few minutes, so they release their sugars and turn golden evenly. If they start to stick or brown too quickly, lower the heat and add a splash of water to deglaze the pan. Patience is key!

Can I prepare this soup in advance?

Yes! The soup base can be made a day ahead and refrigerated. Before serving, reheat gently then add the toasted baguette and cheese topping just before broiling. This helps keep the bread crisp and cheese melty.

Final Thoughts

This Classic French Onion Soup Recipe holds a special place in my kitchen because it’s pure magic how simple onions and broth transform into something so soulful. Whether you’re new to French cooking or a seasoned pro, this recipe welcomes you to slow down, savor every moment, and share a warm, cheesy bowl with anyone you love. I can’t wait for you to try it and make it your own – it’s truly one of those dishes that sticks with you.