French Onion Soup

French Onion Soup is a classic comfort dish that brings together sweet, caramelized onions, a rich, savory broth, and a golden, bubbly layer of melted cheese on top of a…

By Madison • September 19, 2025 • Reading time: 7 min

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French Onion Soup is a classic comfort dish that brings together sweet, caramelized onions, a rich, savory broth, and a golden, bubbly layer of melted cheese on top of a toasted bread slice. It’s warm and satisfying with a perfect blend of flavors and textures that feel like a big, cozy hug on a chilly day.

I love making French Onion Soup when I want something special but not too complicated. The slow-cooked onions fill the kitchen with an amazing aroma that makes you impatient to eat! My tip is to take your time caramelizing the onions; it really brings out their natural sweetness and transforms the soup into something magical.

One of my favorite ways to enjoy this soup is served right in small oven-safe bowls, fresh out of the oven with that cheesy top perfectly browned and bubbly. It’s the kind of meal that’s perfect for a quiet night in or impressing friends with simple, cozy flavors. Whenever I make it, everyone ends up asking for seconds, and I don’t blame them!

How Do You Get Perfectly Caramelized Onions Every Time?

Caramelizing onions is the heart of this soup and it requires patience. Here’s my simple approach:

• Use a heavy, wide pan to allow even cooking.
• Cook over medium to medium-low heat to avoid burning but still let sugars brown.
• Stir often—every few minutes—to prevent sticking and uneven color.
• Add a pinch of salt and sugar early; sugar helps fasten caramelization.
• It takes about 40-50 minutes. Don’t rush by turning heat too high—slow and steady wins!

This slow cooking lets onions become soft, sweet, and beautifully golden. The depth of flavor they add makes the soup truly delicious.

Equipment You’ll Need

• Large heavy-bottomed pot or Dutch oven – perfect for even heat and slow caramelizing.
• Wooden spoon – great for stirring onions without scratching your pot.
• Chef’s knife – makes slicing onions thin and even easier.
• Baking sheet – for toasting the baguette slices.
• Oven-safe soup bowls or crocks – needed to broil the cheese topping safely.
• Broiler or oven with broil setting – melts and browns the cheese perfectly.

Flavor Variations & Add-Ins

• Swap beef broth for mushroom or vegetable broth to make a vegetarian-friendly soup with rich umami taste.
• Add cooked bacon or pancetta for a smoky, meaty boost of flavor.
• Use Swiss or mozzarella cheese instead of Gruyère if you want a milder, stretchy melt.
• Sprinkle in fresh herbs like rosemary or thyme during simmering to change the aromatic profile.

French Onion Soup

Ingredients You’ll Need:

Main Ingredients:

• 6 large yellow onions, thinly sliced
• 4 tablespoons unsalted butter
• 2 tablespoons olive oil
• 1 teaspoon salt
• ½ teaspoon sugar
• 3 cloves garlic, minced
• ½ cup dry white wine (optional)
• 8 cups beef broth (or a mix of beef and chicken broth for lighter flavor)
• 2 bay leaves
• 4-5 sprigs fresh thyme, tied together
• Salt and freshly ground black pepper, to taste

For the Topping:

• 1 baguette, cut into 1-inch thick slices
• 2 cups grated Gruyère cheese (or Swiss cheese)
• Fresh thyme leaves, for garnish (optional)

How Much Time Will You Need?

This recipe requires about 15 minutes to prepare and around 1 hour to cook, mainly to caramelize the onions slowly and bring out their sweetness. Additional time is needed to toast the bread and broil the cheese topping—about 10 minutes combined. Overall, plan for roughly 1 hour and 25 minutes from start to finish.

Step-by-Step Instructions:

1. Caramelize the Onions:

In a large heavy-bottomed pot or Dutch oven, melt the butter with olive oil over medium heat. Add the sliced onions and stir to coat them well. Sprinkle with salt and sugar; the sugar helps the onions caramelize nicely. Cook the onions slowly, stirring frequently, for about 40–50 minutes until they’re deeply golden brown and sweet. Be patient—stir regularly to avoid burning and lower the heat if needed.

2. Add Garlic and Wine:

Stir in the minced garlic and cook for 1–2 minutes until fragrant. Pour in the white wine to deglaze the pan, scraping up any browned bits from the bottom. Let the wine reduce for 3–4 minutes to concentrate the flavor.

3. Simmer the Soup:

Add the beef broth, bay leaves, and tied thyme sprigs. Bring the soup to a boil, then reduce to a simmer for 20–30 minutes to meld the flavors. Season with salt and pepper to taste. Remove the bay leaves and thyme sprigs before serving.

4. Prepare the Bread and Cheese:

While the soup simmers, preheat your oven broiler. Arrange the baguette slices on a baking sheet and toast them until golden and crispy on both sides. Then ladle the hot soup into oven-safe bowls. Place two toasted baguette slices on each bowl and generously sprinkle grated Gruyère cheese over the bread.

5. Broil and Serve:

Place the bowls under the broiler until the cheese melts, bubbles, and turns golden brown—about 3–5 minutes. Keep a close eye to prevent burning. Garnish with fresh thyme leaves if you like, then serve immediately and enjoy the cozy warmth of this classic French comfort dish!