French Onion Soup

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There’s nothing quite like the warmth of a classic French Onion Soup to soothe the soul. Slow-cooked, caramelized onions meld with rich beef broth, creating a depth of flavor that’s both comforting and timeless. This recipe captures the essence of traditional French cooking, offering a bowl of pure, unadulterated comfort.

Table of Contents

two bowls with french onion soup each bowl with 3 slices of toasted bread with cheese.

There’s something truly special about transforming a simple pile of onions into a pot of velvety, savory bliss, and I can’t wait for you to experience it. Imagine the aroma filling your kitchen as the onions slowly caramelize, turning a deep golden brown—it’s the kind of scent that warms you from the inside out. This isn’t just about following a recipe; it’s about embracing the soothing rhythm of cooking and creating something utterly comforting.

Trust me, once you dip your spoon into the rich broth, topped with that irresistible layer of melted Gruyère over crispy baguette slices, you’ll understand why this dish has stood the test of time. It’s like a cozy evening in Paris, right from your own kitchen. So grab your favorite pot and let’s get started—because the best meals aren’t just eaten, they’re shared and savored, and I have a feeling this soup will become a new favorite in your home.

Before You Start

Embrace the Art of Caramelization: Patience is your best friend here. The key to a deeply flavorful soup lies in allowing the onions to caramelize slowly over medium-low heat. This process can take up to an hour, but it’s worth every fragrant minute. Stir occasionally to prevent sticking, but let the onions sit enough to develop that rich, golden color.
Choose the Right Onions: Yellow onions are the classic choice for their balance of sweetness and robustness. If you’re feeling adventurous, mixing in some sweet Vidalia or red onions can add interesting layers of flavor.
Quality Over Quantity in Broth: Since the broth forms the soul of your soup, opt for a high-quality beef broth or, better yet, homemade stock if you have it. Low-sodium varieties give you more control over the seasoning.
The Wine Factor: A dry white wine adds a subtle acidity that balances the sweetness of the onions. If you prefer a richer flavor, a dry red wine works beautifully too. No wine on hand? A splash of apple cider or additional broth can substitute, though the depth of flavor will vary.
Deglazing is Non-Negotiable: When you pour in the wine to deglaze, make sure to scrape every bit of the browned goodness from the bottom of the pot. Those little bits are packed with flavor and add complexity to your soup.
Cheese Choices Matter: Gruyère is traditional for its nutty, melty perfection, but don’t let that limit you. Comté, Emmental, or even a robust Swiss can work wonders. The goal is a cheese that melts well and complements the soup’s hearty flavors.
Oven-Safe Bowls: If you plan to broil the soup with the cheesy bread on top, ensure your bowls are oven-safe to handle the heat. Alternatively, you can melt the cheese over the baguette slices separately and place them on top just before serving.
Season Thoughtfully: Remember that the cheese and broth can be salty. Taste your soup before adding extra salt at the end to avoid over-seasoning.
Enjoy the Process: Lastly, don’t forget to enjoy the cooking journey. Perhaps pour yourself a glass of that wine, turn on some music, and savor the delightful aromas filling your kitchen.

ingredients needed to make french onion soup.

Ingredients You’ll Need

Onions: We’re starting with thinly sliced onions—the heart of this soup. As they caramelize, they’ll develop a deep, sweet flavor that’s utterly comforting. Yellow onions are the classic choice, but you could mix in some sweet or red onions for extra complexity.
Butter: This adds richness and helps the onions soften and caramelize beautifully. If you prefer, you can substitute with ghee for a nuttier flavor.
Olive Oil: Working alongside butter, olive oil prevents it from burning and introduces a subtle fruity note. If needed, you can use all butter or swap in a neutral oil like canola.
Garlic: Minced garlic enhances the savory depth of the soup. For a twist, roasted garlic can add a sweeter, mellower flavor.
Sugar: A touch of sugar aids in caramelizing the onions, bringing out their natural sweetness. If you prefer a less sweet soup, feel free to omit it.
Salt: Essential for drawing out moisture from the onions and layering flavor throughout the cooking process. Remember to adjust based on the saltiness of your broth.
Dry White Wine: This deglazes the pot, lifting all those flavorful bits stuck to the bottom, and adds a subtle acidity. If you don’t have white wine on hand, dry red wine or a splash of apple cider vinegar can work as substitutes.
Beef Broth: Forms the savory base of our soup. Using low-sodium or no-sodium-added broth gives you better control over seasoning. Vegetable or chicken broth can also be used.
Bay Leaves: They infuse the soup with a mild herbal essence. Don’t forget to remove them before serving!
Dried Thyme: Adds an earthy, aromatic layer. If you have fresh thyme, even better—just use a bit more.
Baguette: Sliced and toasted, it becomes the perfect raft for melted cheese. Any crusty bread like ciabatta or sourdough makes a good alternative.
Gruyère Cheese: Grated over the baguette slices, it melts into a bubbly, golden topping. Emmental, Comté, or a good Swiss cheese also melt well and taste great.

How To Make French Onion Soup

Soften the Onions

In a large pot or Dutch oven, melt 3 tablespoons of butter with 1 tablespoon of olive oil over medium heat. The combination of butter and oil raises the smoke point, preventing the butter from burning while adding rich flavor. Add 4 large onions, thinly sliced, to the pot. Cook them for about 10 minutes until they become soft and translucent.

Tip: Uniformly sliced onions cook more evenly, so take your time with the prep work.

Caramelize the Onions

Sprinkle 1 teaspoon of sugar and 1 teaspoon of salt over the onions. Continue to cook, stirring frequently, for another 30 to 40 minutes until the onions are deeply caramelized and golden brown.

Tip: Patience is key here—the slow caramelization process brings out the onions’ natural sweetness, which is essential for the soup’s depth of flavor.

Add the Garlic

Stir in 2 cloves of minced garlic and cook for an additional 1 minute until fragrant.

Tip: Adding the garlic later prevents it from burning and becoming bitter.

Deglaze and Add Broth

Pour in 1 cup of dry white wine to deglaze the pot, scraping up any browned bits from the bottom. Let the wine simmer until it is mostly evaporated. Add 8 cups of low-sodium beef broth, 2 bay leaves, and 1 teaspoon of dried thyme to the pot. Bring the soup to a boil, then reduce the heat and let it simmer for about 30 minutes. After simmering, taste the soup and adjust the seasoning with additional salt and pepper if needed.

Tip: Those browned bits are flavor gold—deglazing incorporates them back into the soup.

Prepare Baguette Slices

While the soup is simmering, preheat your oven to 400°F (200°C). Slice a baguette into pieces and arrange them on a baking sheet. Toast them in the oven for about 5 to 7 minutes, or until golden and crisp.

Remove the toasted baguette slices from the oven. Sprinkle each slice generously with grated Gruyère cheese (you’ll need about 2 cups total). Return them to the oven for a few more minutes until the cheese is melted and bubbly.

Tip: For an extra layer of flavor, you can rub a cut clove of garlic over the toasted baguette slices before adding the cheese.

Assemble The Soup

Ladle the hot soup into oven-safe bowls. Place a few cheesy baguette slices on top of each bowl. Preheat your broiler. Place the bowls on a baking sheet and broil for 2 to 3 minutes, or until the cheese is melted and golden brown. Carefully remove the bowls from the oven (they will be hot!) and let them cool for a few minutes before serving.

Tip: A sprinkle of freshly chopped thyme or a crack of black pepper on top adds a lovely finishing touch.

Frequently Asked Questions

Can I make French Onion Soup ahead of time?

Absolutely! In fact, this soup often tastes even better the next day as the flavors continue to meld. After cooking, let the soup cool to room temperature, then refrigerate it in an airtight container for up to 3 days. When you’re ready to enjoy it again, simply reheat it on the stove over medium heat until warmed through. Proceed with the baguette and cheese steps just before serving to keep the topping fresh and crisp.

Can I freeze French Onion Soup?

Yes, you can freeze the soup base (without the bread and cheese) for up to 3 months. Allow the soup to cool completely before transferring it to freezer-safe containers or heavy-duty freezer bags, leaving a bit of space at the top for expansion. When you’re ready to serve, thaw the soup overnight in the refrigerator, then reheat on the stove over medium heat. Prepare the cheesy baguette slices fresh for the best texture.

How do I prevent the bread from becoming too soggy?

To keep the baguette slices from getting overly soggy, make sure to toast them until they’re golden and crisp before adding the cheese. This creates a barrier that helps them hold up better once submerged in the soup. Additionally, you can place the cheesy toasts on top of the soup just before serving or even serve them on the side, allowing everyone to dip at their leisure.

My onions aren’t caramelizing—what am I doing wrong?

Caramelizing onions takes time and patience. If your onions aren’t browning after 30 minutes, a few things might be happening. First, make sure you’re cooking over medium to medium-low heat; too high, and they’ll burn, too low, and they’ll simply soften without browning. Also, avoid overcrowding the pot—a wide, heavy-bottomed pot allows the onions to spread out and cook evenly. Stir them occasionally, but not constantly, to let them develop color.

I hope you’re as excited as I am to cozy up with a bowl of this heartwarming French Onion Soup. There’s something truly rewarding about transforming simple ingredients into a dish that feels like a warm embrace.

I’d love to hear how your soup turns out—did you find joy in the slow caramelization of the onions, or perhaps you added your own special touch? Please share your thoughts and experiences in the comments below.