Dinner

Classic French Onion Soup with Caramelized Onions, Gruyère, and Crispy Baguette Recipe

Name: Classic French Onion Soup with Caramelized Onions, Gruyère, and Crispy Baguette Recipe
Prep time: 20 min
Cook time: 1 h 30 min
Total time: 1 h 50 min
Cuisine: French
Ingredients: 4 lbs yellow onions, thinly sliced; 4 tablespoons unsalted butter; 2 tablespoons olive oil; 1 teaspoon salt, plus more to taste; 1 teaspoon sugar; 4 cloves garlic, minced; 1/2 cup dry white wine (or dry sherry); 2 tablespoons brandy or cognac (optional but authentic); 6 cups beef broth (high-quality); 2 cups chicken broth; 2 bay leaves; 4-5 sprigs fresh thyme (or 1 teaspoon dried thyme); 1 tablespoon Worcestershire sauce; 1/2 teaspoon black pepper; Salt to taste; 1 French baguette, sliced 3/4-inch thick; 2 tablespoons butter, melted; 1 clove garlic, halved; 2 cups Gruyère cheese, shredded (about 8 oz); 1/2 cup Parmesan cheese, grated; Fresh thyme leaves for garnish

Byluca Carter January 14, 2026January 14, 2026

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Introduction

Classic French onion soup is the ultimate comfort food, featuring deeply caramelized onions in a rich beef broth topped with crusty bread and melted Gruyère cheese. This elegant Parisian café favorite offers warm, savory flavors perfect for cozy evenings or impressive dinner parties.

A dark brown pottery bowl filled with French onion soup topped with two golden toasted round bread slices placed on the surface; the soup is covered by a thick layer of melted creamy, slightly browned cheese bubbling and dripping down the sides of the bowl. In the center, a round onion slice also topped with a thick, bubbling, browned cheese layer sits prominently above the soup. Some caramelized onions peek through under the cheese layer. Steam rises from the hot soup. The bowl is set against a white marbled textured surface. photo taken with an iphone --ar 4:5 --v 7

Ingredients

4 lbs yellow onions, thinly sliced
4 tablespoons unsalted butter

2 tablespoons olive oil
1 teaspoon salt, plus more to taste

1 teaspoon sugar
4 cloves garlic, minced

1/2 cup dry white wine (or dry sherry)
2 tablespoons brandy or cognac (optional)
6 cups beef broth

2 cups chicken broth
2 bay leaves
4-5 sprigs fresh thyme (or 1 tsp dried)

1 tablespoon Worcestershire sauce
1/2 teaspoon black pepper
Salt to taste

1 French baguette, sliced 3/4-inch thick
2 tablespoons butter, melted
1 clove garlic, halved

2 cups Gruyère cheese, shredded (about 8 oz)
1/2 cup Parmesan cheese, grated
Fresh thyme leaves for garnish

Instructions

Step 1: Peel and thinly slice the onions into half-moons about 1/4-inch thick. To reduce tearing, chill onions beforehand or cut near ventilation.
Step 2: In a large heavy-bottomed pot, melt butter with olive oil over medium heat. Add sliced onions, salt, and sugar. Cover and cook for 10 minutes, stirring occasionally to release moisture.
Step 3: Remove lid, reduce heat to medium-low, and cook onions uncovered, stirring every 5-10 minutes for 40-50 minutes until deep golden brown and caramelized. Add water if onions stick to deglaze the pot.

Step 4: Stir in minced garlic and cook 1-2 minutes until fragrant. Add white wine and brandy, scraping browned bits from the pot. Simmer until the liquid reduces by half, about 3-4 minutes.
Step 5: Add beef and chicken broths, bay leaves, thyme, Worcestershire sauce, and black pepper. Bring soup to a boil, then reduce heat and simmer uncovered for 30 minutes. Remove bay leaves and thyme sprigs, season with salt and pepper.
Step 6: Preheat oven to 400°F. Brush baguette slices with melted butter and toast on a baking sheet for 5-7 minutes per side until golden. While warm, rub toasted bread with halved garlic clove for flavor.

Step 7: Preheat broiler to high. Ladle hot soup into oven-safe crocks about 3/4 full. Top with 1-2 slices of toasted baguette, then generously pile shredded Gruyère over the bread. Sprinkle with grated Parmesan.
Step 8: Place crocks on a baking sheet and broil 3-5 minutes until cheese is melted, bubbly, and golden brown. Watch closely to prevent burning.
Step 9: Let soup cool for 1-2 minutes before serving. Garnish with fresh thyme leaves and serve immediately with extra baguette slices.

Tips & Variations

Use day-old bread and toast it well to avoid sogginess under the cheese.
For a vegetarian version, substitute beef broth with vegetable broth and add mushrooms for extra umami.
Replace Gruyère with Comté or Emmental cheese for a different but authentic flavor.

Slow and low is key—don’t rush caramelizing onions to avoid bitterness.
Oven-safe crocks are essential for broiling; regular bowls may crack under high heat.

Storage

Store leftover soup base (without bread and cheese) in airtight containers in the refrigerator for up to 5 days or freeze for up to 3 months. Reheat gently on the stovetop before adding fresh bread and cheese to broil. Toasted bread can be made a day ahead and stored in an airtight container. Avoid freezing the soup with cheese as it affects texture and melting.

How to Serve

A steaming bowl of French onion soup is shown in a dark brown ceramic pot, filled with rich brown broth and caramelized onion pieces. On top, there is a thick layer of melted, golden-brown cheese that is bubbly and slightly charred in spots. Resting on the cheese are two slices of toasted white bread, with a crispy light brown crust and soft airy interior holes visible. One of the bread slices has a stack of caramelized onion rings underneath the cheese, adding a textured look. Cheese drips down the side of the pot, emphasizing the hot, gooey cheese layer. The whole scene is set on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I speed up the caramelization process?

Not effectively. Proper caramelization requires low and slow cooking for 40-50 minutes to develop deep sweetness and flavor. High heat will burn the onions rather than caramelize them.

What if I don’t have oven-safe bowls?

You can toast the bread with cheese on a baking sheet separately, then float the cheese toast on top of the soup in regular bowls just before serving.