Classic French Onion Soup (Printable version)

Deeply caramelized onions in savory broth, topped with toasted bread and melted Gruyère cheese.

# What You Need:

→ Onions

01 - 3 large yellow onions, thinly sliced
02 - 1 tablespoon unsalted butter
03 - 1 tablespoon olive oil

→ Soup Base

04 - 2 cloves garlic, minced
05 - 1 teaspoon sugar
06 - 1/2 teaspoon salt
07 - 1/4 teaspoon freshly ground black pepper
08 - 2 tablespoons all-purpose flour
09 - 1/2 cup dry white wine
10 - 5 cups beef or vegetable stock
11 - 2 sprigs fresh thyme
12 - 1 bay leaf

→ Topping

13 - 4 slices French baguette, 1 inch thick
14 - 1 tablespoon olive oil for bread
15 - 1 cup Gruyère cheese, grated

# Step-by-step guide:

01 - In a large pot or Dutch oven, heat butter and olive oil over medium heat. Add sliced onions and stir to coat. Cook, stirring frequently, until onions are soft and deeply caramelized, about 35-40 minutes. Add sugar and salt halfway through to enhance caramelization.
02 - Add minced garlic and cook for 1 minute until fragrant.
03 - Sprinkle flour into the pot and cook, stirring constantly, for 2 minutes to thicken slightly.
04 - Pour in white wine while scraping the bottom of the pot with a wooden spoon to release any browned bits and build flavor.
05 - Pour in the stock and add thyme sprigs 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 additional salt as needed.
06 - Preheat oven broiler. Arrange baguette slices on a baking sheet, brush both sides with olive oil, and toast under the broiler until golden, approximately 1-2 minutes per side.
07 - Ladle hot soup into oven-safe bowls. Top each bowl with one toasted baguette slice, then cover generously with grated Gruyère cheese.
08 - Place bowls on a baking sheet and broil for 2-3 minutes, or until cheese is melted, bubbly, and golden brown. Serve immediately.

# Expert Advice:

01 -
  • The caramelization happens slowly enough that you can taste each stage, building confidence in your technique.
  • It's the kind of dish that feels fancy enough for guests but simple enough that you won't stress about it.
  • One pot, one hour, and suddenly you have something restaurant-quality bubbling in your oven.
02 -
  • Don't walk away during caramelization—one distracted moment and your onions can tip from golden to burnt with no way back.
  • Using day-old baguette instead of fresh bread changes everything; fresh bread will absorb soup and turn to mush instead of staying crispy.
  • The cheese only needs a quick broil to bubble and brown; leaving it in too long makes it tough and separates the oils.
03 -
  • A splash of brandy or sherry added with the wine takes this from good to unforgettable, especially if you're cooking for people you want to impress.
  • Make the soup a day ahead and reheat it gently; the flavors actually deepen and mellow overnight, and you'll have less stress on serving day.
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