Description
Classic French Onion Soup features slowly caramelized onions simmered in a flavorful beef broth with wine and sherry, topped with toasted baguette slices and melted Gruyère cheese for a rich, comforting, and elegant dish perfect as an appetizer or light meal.
Ingredients
Soup
- 4 tablespoons butter (unsalted or salted)
- 1 tablespoon olive oil or vegetable oil
- 3 pounds yellow onions or sweet Vidalia onions, peeled, halved and thinly sliced (about ⅛-inch thick)
- ¾ teaspoon Kosher or sea salt (plus more to taste)
- ¼ teaspoon freshly ground black pepper (plus more to taste)
- ¾ cup dry white wine (or broth as substitute)
- 1 tablespoon dry sherry (or cider vinegar as substitute)
- 2 tablespoons all-purpose flour
- 8 cups beef broth or beef stock
- 1 bay leaf
- 2 fresh thyme sprigs (or ½ teaspoon dried thyme)
- ½ teaspoon Worcestershire sauce
For Serving
- 1 small baguette, sliced ½-inch thick
- 6 ounces Gruyère cheese, grated (about 1 ½ cups) (can replace with Fontina or Mozzarella)
- Optional: fresh thyme leaves or chopped chives for garnish
Instructions
- Prep: Prepare all ingredients by peeling and thinly slicing the onions, slicing the baguette, and grating the cheese.
- Sauté onions: In a large pot or Dutch oven over medium heat, melt the butter with the oil. Add the sliced onions, salt, and pepper, stirring to coat.
- Caramelize onions: Cook uncovered, stirring occasionally, until the onions are deeply golden brown and caramelized, approximately 45 to 55 minutes. Stir more frequently towards the end to avoid burning, adjust heat as needed, and deglaze with water if onions stick to the pot.
- Add wine and sherry: Pour in the white wine and dry sherry, increase heat to medium-high, and boil until nearly all liquid evaporates, about 5-6 minutes.
- Incorporate flour: Sprinkle flour over onions and cook, stirring constantly for about 1 minute to eliminate raw flour taste.
- Add broth and aromatics: Gradually stir in a cup of beef broth, then add the remaining broth along with bay leaf, thyme, and Worcestershire sauce. Bring to a boil.
- Simmer soup: Reduce heat and simmer the soup gently for 20 minutes to meld flavors.
- Prep bread: While soup simmers, preheat oven to 400ºF. Place baguette slices in a single layer on a baking sheet and bake 8-10 minutes until crisp and golden at edges.
- Season soup: Remove bay leaf and thyme sprigs from soup, taste, and adjust salt and pepper as needed.
- Prepare broiler: Position oven rack about 6 inches from heat source and turn on broiler (low or high).
- Assemble bowls: Ladle hot soup into ovenproof bowls placed on a baking sheet. Top each with 1-2 slices of toasted bread without overlapping, and generously sprinkle grated Gruyère cheese atop the bread.
- Broil cheese: Broil until cheese melts and browns around the edges, watching carefully to prevent burning.
- Serve: Serve immediately garnished with fresh thyme leaves or chopped chives if desired. If ovenproof bowls are unavailable, broil cheese on bread separately and add to soup bowls before serving.
Notes
- Use yellow or sweet Vidalia onions for best caramelization and flavor balance.
- Deglaze pot with a splash of water if onions stick and start to burn to lift flavorful bits.
- Substitute white wine with broth and dry sherry with cider vinegar if preferred or to keep recipe non-alcoholic.
- Baguette slices should be toasted before adding cheese to prevent sogginess.
- Gruyère provides the classic flavor but Fontina or Mozzarella are good alternatives.
- Watch cheese carefully under broiler as it can brown/burn quickly.
- This soup is best enjoyed fresh but can be made ahead and reheated gently, adding bread and cheese just before serving.
- Prep Time: 20 minutes
- Cook Time: 1 hour 30 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: French