Name: French Onion Soup
Prep time: 20 min
Cook time: 1 h 40 min
Total time: 2 h
Cuisine: French
Ingredients: 4 tablespoons unsalted butter; 1 tablespoon vegetable oil; 3 pounds Vidalia (or other sweet) onions, halved lengthwise and thinly sliced; ¾ teaspoon salt; ½ teaspoon freshly ground black pepper; ¾ teaspoon granulated sugar; 1 cup dry white wine; 2 tablespoons all-purpose flour; 6 cups beef broth; 1 teaspoon Worcestershire sauce; ½ teaspoon dried thyme; 2 bay leaves; 1 small baguette, cut into ½-inch slices; 1 tablespoon dry sherry; 8 ounces Gruyère cheese, grated (about 2 cups); ½ cup grated Parmigiano-Reggiano

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French Onion Soup is a timeless classic in French cuisine, renowned for its rich flavor, caramelized onions, and savory broth topped with crusty bread and melted cheese. This comforting dish combines simple ingredients to create a deeply satisfying and elegant soup, ideal for chilly evenings or as an impressive appetizer.

Why You’ll Love This Recipe

This French Onion Soup offers a balance of sweet, savory, and umami flavors, all wrapped in a warm, hearty broth. The process of slowly caramelizing onions creates a depth of flavor that’s difficult to replicate with shortcuts. Whether served as a starter or a main course, it’s a dish that brings comfort and sophistication to the table. You’ll appreciate its economical ingredients and how easily it transforms into a restaurant-quality meal at home.

ingredients

(Tip: You can find the complete list of ingredients and their measurements in the recipe card below.)

Yellow onions
Unsalted butter
Olive oil
Garlic
Bay leaf
Fresh thyme
Dry white wine
Beef broth
French baguette or crusty bread
Gruyère cheese
Salt
Black pepper
All-purpose flour (optional, for slight thickening)

directions

Slice the onions thinly and evenly.
In a large pot, melt butter with olive oil over medium-low heat.
Add the onions and cook slowly, stirring often, until deeply caramelized (about 40 minutes).
Add minced garlic, bay leaf, and thyme; cook for another minute.
Deglaze the pot with white wine, scraping up any bits stuck to the bottom. Let it simmer until reduced.
Stir in beef broth and bring to a gentle simmer. Season with salt and pepper.
Simmer uncovered for 30–40 minutes to develop flavor. Optionally, add a tablespoon of flour for a thicker consistency.
While the soup simmers, slice and toast baguette slices until golden.
Ladle soup into oven-safe bowls, top each with a toasted baguette slice, and cover with grated Gruyère.
Broil until the cheese is melted and bubbly. Serve immediately.

Servings and timing

This recipe yields approximately 4 servings.
Preparation time: 15 minutes
Cooking time: 1 hour 20 minutes
Total time: 1 hour 35 minutes

Variations

Vegetarian Option: Substitute beef broth with a rich vegetable broth and use vegan cheese or omit cheese entirely.
Red Wine Version: Replace white wine with red wine for a deeper flavor.
Herb Infusion: Experiment with different herbs like rosemary or sage for added aroma.
Cheese Alternatives: Try Emmental, Comté, or mozzarella if Gruyère is not available.
Bread Options: Use sourdough or ciabatta instead of baguette for a different texture.

storage/reheating

Store leftover soup (without the bread and cheese topping) in an airtight container in the refrigerator for up to 4 days.
To reheat, warm it gently on the stovetop over medium heat until hot.
For best results, add fresh toasted bread and cheese before serving, then broil as instructed.
This soup can also be frozen for up to 3 months. Thaw in the refrigerator overnight and reheat as above.

FAQs

How do I properly caramelize onions?

Cook sliced onions over low to medium-low heat in butter and oil, stirring regularly for 40–45 minutes until they turn a deep golden brown.

Can I use chicken broth instead of beef broth?

Yes, chicken broth can be used, though it will result in a lighter flavor profile.

Is it necessary to use wine in French Onion Soup?

Wine adds depth, but you can omit it and add a splash of vinegar or lemon juice for acidity.

What kind of onions are best?

Yellow onions are traditional for their balance of sweetness and flavor after caramelization.

Can I make this soup ahead of time?

Yes, it actually tastes better the next day as the flavors continue to develop.

How do I prevent the cheese from sinking?

Use a sturdy, well-toasted bread slice and layer the cheese generously so it melts evenly on top.

Can I use a slow cooker?

Yes, caramelize onions beforehand, then transfer everything to a slow cooker and cook on low for 4–6 hours.

What bread should I use?

A French baguette or any crusty, day-old bread works best as it holds up to the broth.

Is French Onion Soup gluten-free?

Only if you skip the flour and use gluten-free bread. Check your broth to ensure it’s gluten-free as well.

Can I double the recipe?

Absolutely, simply scale the ingredients accordingly. Use a larger pot and extend simmering time if needed.

Conclusion

French Onion Soup is a luxurious yet humble dish that proves how powerful simple ingredients can be when treated with care. Its deep, savory richness makes it ideal for cozy nights or special occasions. With options for customization, this classic can be tailored to fit various dietary needs and preferences. Give it a try and experience a touch of French culinary tradition in your own kitchen