French Onion Soup

Living in France for the past five years has taught me a lot — how to correctly pronounce “merci,” that baguettes have a magical half-life of about 12 hours, and most importantly, how to make a good French onion soup.

French onion soup isn’t just soup. It’s a warm hug in a bowl, a culinary time machine that whisks you away to a cozy Parisian bistro on a rainy day. Of all the recipes I’ve learned to love here, this one holds a special place in my heart (and stomach).

Why? Because it’s simple, soulful, and seriously delicious.

Whether you’re a kitchen newbie or you’ve caramelized more onions than you’d care to admit, this recipe will walk you through the process. By the end, you’ll have a bowl of French onion soup that’s so good, you’ll swear you can hear an accordion playing in the background.

Ready to dive in?

Equipment You’ll Need

1. Heavy-Bottomed Pot or Dutch Oven: A heavy-bottomed pot ensures even heat distribution, which is key for caramelizing onions without burning them. A Dutch oven is ideal—it retains heat well and makes the process easier.

2. Oven-Safe Bowls: You’ll need bowls that can handle the high heat of the broiler for that cheesy, bubbly topping. Look for ceramic or stoneware bowls labeled as broiler-safe.

3. Wooden Spoon: A sturdy wooden spoon is your best friend for stirring onions and scraping up those caramelized bits during deglazing. Metal can scratch your pot, and plastic might not hold up under the heat.

4. Box Grater: For grating Gruyère (or any cheese), a good box grater will make your life easier. Freshly grated cheese melts more smoothly than pre-shredded varieties.

5. Baking Sheet: Place your oven-safe bowls on a baking sheet when broiling. This catches any bubbling-over cheese and makes it easier to transfer the hot bowls in and out of the oven.

Ingredients You’ll Need

• 4 large yellow onions (about 2 pounds), thinly sliced
• 3 tablespoons unsalted butter
• 1 tablespoon olive oil
• 6 cups beef broth (or vegetable broth for a vegetarian version)
• 1/2 cup dry white wine (optional, but it adds depth)
• 2 sprigs fresh thyme (or 1/2 teaspoon dried thyme)
• 1 bay leaf
• 1 French baguette, sliced into 1-inch thick rounds
• 2 cups Gruyère cheese, grated (or a mix of Gruyère and Parmesan)
• Salt and freshly ground black pepper, to taste

Breaking It Down

Onions (The Stars of the Show):
Yellow onions are the MVPs here—they’re sweet, mellow, and perfect for caramelizing. Think of them as the Beyoncé of the soup world: the flavor rests entirely on their shoulders. Slice them thinly so they cook evenly. Don’t be tempted to use sweet onions, though—they can make the soup cloying instead of balanced.

Butter and Olive Oil (The Dynamic Duo):
Butter gives richness, while olive oil helps prevent the butter from burning as the onions cook. It’s like having two friends with different skills tag-team a project. Together, they create the perfect base for that golden caramelization.

Broth (The Flavor Backbone):
A good-quality beef broth is essential. It adds depth and richness that water simply can’t provide. If you’re going vegetarian, opt for a robust vegetable broth—but make sure it’s one you’d actually enjoy sipping on its own. No one wants a bland soup!

Dry White Wine (The Secret Weapon):
This is the ingredient that’ll make your soup taste like it came straight out of a Parisian bistro. It adds a subtle acidity that balances the sweetness of the onions. Don’t worry if you don’t drink wine—you can use a splash of sherry, brandy, or even just a bit more broth.

Thyme and Bay Leaf (The Aromatic Heroes):
Fresh thyme and bay leaf give the soup its earthy, herby notes. They’re the quiet background singers that elevate the whole dish without stealing the spotlight. If you’re out of fresh thyme, dried works too—just use a little less.

Baguette (Crunchy, Toasty Goodness):
A crusty French baguette is essential for those iconic floating croutons. Slice it thick enough to hold up under a layer of cheese and broiling. Bonus points if it’s a day or two old—slightly stale bread actually holds up better!

Gruyère Cheese (The Gooey Crown):
Gruyère is nutty, melty, and absolutely essential. It’s the kind of cheese that makes you want to do a happy dance when it bubbles and browns under the broiler. Can’t find Gruyère? A mix of Swiss and Parmesan works too, but promise me you won’t skimp on the cheese.

Salt and Pepper (The Finishing Touch):
Seasoning is the difference between “meh” and “wow.” Add salt in small increments—your broth may already be salty—and crack in plenty of fresh black pepper for a bit of warmth.

With these ingredients prepped and ready, you’re already halfway to an irresistible French onion soup.

Up next? Turning this list of staples into something that’ll make your kitchen smell like a little slice of France.

How to Make the Perfect French Onion Soup

Preparation

1. Properly Slicing Onions for Even Cooking:

• Start by peeling your onions and cutting them in half lengthwise (from root to stem). Place each half flat-side down on your cutting board and slice thinly into half-moons, about 1/8-inch thick. Uniform slices are key to even caramelization.
• Pro tip: Use a sharp knife to avoid crushing the onions, which can release excess moisture and slow caramelization.

2. Choosing the Right Broth for Depth of Flavor:

• Beef broth is the traditional choice for its rich, savory flavor. Use a high-quality store-bought broth or, if you’re feeling ambitious, homemade beef stock.
• If you’re vegetarian, opt for a hearty vegetable broth. To mimic the depth of beef stock, you can add a teaspoon of soy sauce or miso paste to your vegetable broth.

Caramelizing the Onions

1. Heat and Fat Balance:

• Heat 3 tablespoons of butter and 1 tablespoon of olive oil in a heavy-bottomed pot (like a Dutch oven) over medium heat. The oil prevents the butter from burning while adding a touch of richness.

2. Adding Onions and Stirring:

• Add your sliced onions to the pot and toss to coat them evenly in the fat. Sprinkle with a pinch of salt to draw out their moisture.

3. Patience is Key:

• Cook the onions over medium-low heat, stirring every 5-10 minutes. They’ll go through stages: softening, becoming translucent, then gradually turning golden brown. This process takes about 35-45 minutes, so put on some music and let the onions do their thing.
• If the onions start sticking or browning too quickly, reduce the heat and add a tablespoon of water to loosen them.

4. Golden Brown Goodness:

• The goal is deep golden brown onions with a sweet, jammy texture. Don’t rush this step—it’s where all the flavor magic happens!

Deglazing the Pan

1. What is Deglazing?

• Deglazing lifts all the browned bits (fond) stuck to the bottom of the pot, which are packed with flavor.

2. How to Deglaze:

• Once your onions are perfectly caramelized, pour in 1/2 cup of dry white wine (or broth if skipping the wine).
• Stir vigorously, scraping the bottom of the pot with a wooden spoon to loosen all those flavorful bits. Let the liquid simmer for a minute or two until it reduces slightly.

Simmering the Soup

1. Adding Broth and Herbs:

• Pour in 6 cups of warm beef (or vegetable) broth. Add 2 sprigs of fresh thyme and 1 bay leaf. Stir everything together and bring to a gentle simmer.

2. Seasoning and Simmering:

• Taste the soup and season with salt and freshly ground black pepper, adjusting as needed.
• Cover partially and let the soup simmer on low heat for 20-30 minutes to allow the flavors to meld. Longer simmering = deeper flavor. Stir occasionally and remove the thyme and bay leaf before serving.

Preparing the Bread and Cheese Topping

1. Toasting the Baguette:

• Slice a French baguette into 1-inch thick rounds. Arrange the slices on a baking sheet and toast under the broiler for 1-2 minutes per side, just until golden and crisp. Toasting helps the bread hold up under the soup without getting soggy.

2. Grating the Cheese:

• Grate 2 cups of Gruyère cheese (or a mix of Gruyère and Parmesan) using a box grater. Freshly grated cheese melts better than pre-shredded.

Final Assembly

1. Ladling and Topping:

• Preheat your broiler. Ladle the hot soup into oven-safe bowls, leaving a little room at the top. Float a toasted baguette slice on the surface of each bowl and pile on a generous handful of grated Gruyère cheese.

2. Broiling to Perfection:

• Place the bowls on a baking sheet (to catch any drips) and broil in the oven for 2-3 minutes, or until the cheese is melted, bubbly, and golden brown. Keep an eye on it—cheese can go from perfect to burnt in seconds!

3. Safety First:

• Use oven mitts to carefully transfer the hot bowls to your serving surface. They’ll be very hot, so warn your guests to let the bowls cool for a minute before diving in.

And there you have it—French onion soup with all the ooey-gooey, toasty, cheesy glory you’ve dreamed of!

Tips & Common Mistakes to Avoid

1. Rushing the Caramelization Step:

Caramelizing onions is a slow process—think of it as the marathon, not the sprint, of cooking.

Turning up the heat to speed things up will burn the onions instead of developing their natural sweetness. Low and slow is the way to go. Set aside at least 35-45 minutes for this step, and let the magic happen.

2. Skipping the Deglazing:

Those browned bits at the bottom of the pot (fond) are pure flavor gold. Skipping this step means leaving behind a layer of complexity your soup could have had.

Even if you’re not using wine, deglazing with broth is essential to scrape up all that goodness.

3. Using the Wrong Onions:

Yellow onions are the star here because they caramelize beautifully.

Sweet onions can make the soup overly sugary, and white or red onions won’t give the same depth of flavor. Stick to yellow for the best results.

4. Overloading the Cheese:

It’s tempting to go heavy on the cheese (who doesn’t love cheese?), but too much can result in an imbalanced soup.

Aim for a generous but not overwhelming layer—enough to get gooey, golden bubbles without sinking your bread or overpowering the soup.

5. Using Non-Toasted Bread:

Tossing untoasted bread into your soup is a recipe for sogginess. Toasting ensures the bread holds its shape and provides that satisfying crunch beneath the cheese.

Customizations and Recipe Variations

1. Vegetarian Option:

• Swap the beef broth for a high-quality vegetable broth. To add richness, stir in a teaspoon of miso paste or a splash of soy sauce when you add the broth.

2. Vegan Version:

• Use olive oil instead of butter for caramelizing the onions. Replace the Gruyère with a vegan cheese that melts well, such as a cashew-based cheese or shredded vegan mozzarella. Opt for crusty bread that’s dairy-free.

3. Gluten-Free Adaptation:

• Use gluten-free bread for the topping. Many grocery stores now carry excellent gluten-free baguettes that work perfectly. Ensure your broth is gluten-free as well (some store-bought broths contain wheat-based thickeners).

4. Lower Sodium:

• Choose a low-sodium broth to have better control over the saltiness of the soup. You can also omit salting the onions during the caramelization process and season to taste at the very end.

5. Booze-Free:

• If you’re avoiding alcohol, deglaze the pot with a splash of broth instead of wine. Add a teaspoon of white vinegar or lemon juice to mimic the acidity that wine would bring.

With these tips and tricks in mind, you’re ready to tackle French onion soup like a pro!

French Onion Soup Recipe

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