Classic French Onion Soup

Classic French Onion Soup is a rich, comforting staple of French cuisine, celebrated for its deeply caramelized onions and savory broth. This medium-difficulty recipe yields 4 servings of a timeless dish topped with toasted baguette and a signature layer of melted, bubbly Gruyère cheese.

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With a preparation time of 15 minutes and a cooking time of 1 hour 15 minutes, this soup is a labor of love that rewards patience with every spoonful of its savory, onion-rich base.

Ingredients

• Onions: 3 large yellow onions (thinly sliced), 1 tablespoon unsalted butter, 1 tablespoon olive oil
• Soup Base: 2 cloves garlic (minced), 1 teaspoon sugar, 1/2 teaspoon salt, 1/4 teaspoon freshly ground black pepper, 2 tablespoons all-purpose flour, 1/2 cup dry white wine, 1.2 liters (5 cups) beef or vegetable stock, 2 sprigs fresh thyme, 1 bay leaf
• Topping: 4 slices French baguette (1 inch thick), 1 tablespoon olive oil, 120 g (1 cup) Gruyère cheese (grated)

Instructions

Step 1: Caramelize Onions

In a large pot or Dutch oven, heat butter and olive oil over medium heat. Add sliced onions, stirring to coat. Cook, stirring frequently, until onions are soft and deeply caramelized, about 35–40 minutes. Add sugar and salt halfway through to help with caramelization.

Step 2: Add Aromatics

Add garlic and cook for 1 minute until fragrant.

Step 3: Thicken

Sprinkle in the flour and cook, stirring, for 2 minutes to thicken slightly.

Step 4: Deglaze

Deglaze the pot with white wine, scraping the bottom to release any browned bits.

Step 5: Simmer

Pour in the stock, add thyme and bay leaf. Bring to a simmer, then reduce heat and cook uncovered for 20–25 minutes. Remove thyme and bay leaf. Season with pepper and salt as needed.

Step 6: Toast Bread

Preheat oven broiler. Arrange baguette slices on a baking sheet, brush both sides with olive oil, and toast under the broiler until golden, about 1–2 minutes per side.

Step 7: Assemble

Ladle hot soup into oven-safe bowls. Top each with a toasted baguette slice, then cover generously with grated Gruyère.

Step 8: Broil and Serve

Place bowls on a baking sheet and broil for 2–3 minutes, or until cheese is melted, bubbly, and golden brown. Serve immediately.

Zusatztipps für die Zubereitung

For a more complex flavor profile, try using a combination of beef and chicken stock. To ensure proper caramelization, resist the urge to turn up the heat; the onions need time to release their sugars slowly.

Varianten und Anpassungen

Substitute Gruyère with Emmental or Comté if preferred. For a heartier version, add a splash of brandy or sherry with the wine. To accommodate dietary needs, use gluten-free bread and flour, or vegan butter and cheese alternatives for a dairy-free version.

Serviervorschläge

This soup pairs beautifully with a crisp white wine or a light red. Serve it as a sophisticated starter or a main course, ensuring each bowl contains approximately 390 calories and 16g of protein for a balanced meal.

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Whether enjoyed on a cold evening or as part of a festive dinner, this Classic French Onion Soup remains a favorite for its savory depth and satisfying, melted cheese finish.

Recipe Questions & Answers

→ How long does it take to properly caramelize onions?

Properly caramelizing onions takes 35-40 minutes over medium heat with frequent stirring. Adding sugar and salt halfway through helps develop their deep, sweet flavor and rich golden color.

→ Can I make this soup vegetarian?

Yes, simply substitute vegetable stock for beef stock. The deeply caramelized onions provide such rich flavor that the soup remains deeply satisfying even without meat-based broth.

→ What cheese works best if I can't find Gruyère?

Emmental or Comté are excellent alternatives that melt beautifully and offer similar nutty, complex flavors. Swiss cheese also works in a pinch, though the flavor will be slightly milder.

→ Do I need oven-safe bowls for this soup?

Yes, oven-safe bowls are essential for broiling the cheese topping. Look for ceramic, stoneware, or specially designed French onion soup crocks that can withstand high broiler temperatures.

→ Can I prepare this soup ahead of time?

Absolutely. Prepare the soup base up to 3 days ahead and refrigerate. When ready to serve, reheat the soup, then add the bread and cheese topping and broil just before serving for the best texture.

→ Why add flour to the caramelized onions?

The flour creates a light roux that adds body and a subtle thickness to the broth, helping it cling to the onions and bread while providing a more satisfying, velvety texture.