Classic French Onion Soup (Printable)

Savory bistro soup with caramelized alliums, beef broth, toasted baguette, and melted Gruyère cheese.

# What You'll Need:

→ Alliums

01 - 4 large yellow onions, thinly sliced
02 - 2 large leeks, white and light green parts only, cleaned and thinly sliced
03 - 3 shallots, thinly sliced
04 - 3 garlic cloves, minced

→ Fats

05 - 3 tablespoons unsalted butter
06 - 2 tablespoons olive oil

→ Broth & Umami

07 - 8 cups high-quality beef broth
08 - 1 tablespoon Worcestershire sauce
09 - 2 teaspoons soy sauce
10 - 1/2 cup dry white wine
11 - 2 teaspoons fresh thyme leaves
12 - 1 bay leaf

→ Bread & Cheese

13 - 1 baguette, sliced into 1/2-inch rounds
14 - 2 cups Gruyère cheese, grated
15 - 1/2 cup Parmesan cheese, grated

→ Seasonings

16 - Salt and freshly ground black pepper to taste

# Directions:

01 - In a large heavy-bottomed pot or Dutch oven, heat the butter and olive oil over medium heat.
02 - Add the sliced onions, leeks, and shallots. Sauté, stirring frequently, until very soft and deep golden brown, approximately 35 to 40 minutes. Add the minced garlic and cook for 2 minutes more.
03 - Deglaze the pot with white wine, scraping up any browned bits from the bottom.
04 - Stir in the beef broth, Worcestershire sauce, soy sauce, thyme, and bay leaf. Bring to a simmer. Reduce heat and cook uncovered for 30 minutes, stirring occasionally.
05 - Season with salt and pepper to taste. Remove the bay leaf.
06 - Preheat the oven broiler. Arrange baguette slices on a baking sheet and toast under the broiler until golden, approximately 1 to 2 minutes per side.
07 - Ladle the hot soup into oven-safe bowls. Top each with toasted baguette slices and a generous amount of Gruyère and Parmesan cheese.
08 - Place bowls under the broiler until the cheese is melted and bubbly, approximately 3 to 5 minutes.
09 - Serve immediately, garnished with extra thyme if desired.

# Expert Advice:

01 -
  • The caramelization happens slowly, which means you can't rush it, and that's actually the secret to the whole thing tasting restaurant-worthy.
  • One pot becomes a complete meal with that melted cheese top, so cleanup is merciful on a weeknight or elegant enough for company.
  • It tastes even better the next day, which is a gift when life gets hectic.
02 -
  • The caramelization is everything, and it cannot be rushed; medium heat and patience are the only way to get that deep, complex flavor without burning the onions black.
  • Use oven-safe bowls or you'll have a disaster when you put them under the broiler; ceramic works perfectly, but avoid any plastic handles.
  • The soup can be made entirely a day ahead and refrigerated, then reheated gently before assembling and topping with cheese.
03 -
  • Never cover the pot while the onions caramelize; you want the moisture to evaporate so they brown, not steam.
  • Make the soup a day ahead and refrigerate it, then assemble and broil it fresh; the flavors actually deepen overnight.
Go Back