Classic French Onion Soup Recipe

An overhead image of a bowl of french onion soup.

5 from 2 votes

Classic French Onion Soup Recipe

French Onion Soup is absolutely loaded with rich caramelized onions, melted cheese on top of baguette slices, and a deep, savory broth. Made with fresh, real ingredients, it's 1,000x better than anything from a store and can be made ahead and reheated for a light lunch of fantastic dinner side.

Prep Time15

Cook Time1 30

Total Time1 45

Course: Dinner

Cuisine: French

Servings: servings

Calories: 466kcal

Author: Amy Nash

Ingredients

5 Tablespoons salted butter
4-5 large sweet onions, thinly sliced (about 3 pounds)
1 teaspoon granulated sugar
½ teaspoon salt
½ teaspoon black pepper
3 cloves garlic, minced
2 Tablespoons all-purpose flour
½ cup dry white wine (optional)
8 cups beef broth
1 teaspoon Worcestershire sauce
2 bay leaves
2 sprigs fresh thyme (about 1 Tablespoon fresh thyme leaves or ½ teaspoon dried thyme)
1 day-old baguette, sliced into ½-inch thick slices
6-8 ounces gruyere cheese, freshly grated
½ cup freshly grated Parmigiano Reggiano cheese

Instructions

Add butter to a large pot or dutch oven over medium heat. Once the butter has melted, add the sliced onions, sugar, salt, and pepper. Stir well to coat the onions in the melted butter and evenly distribute the other ingredients.
Cook the onions, stirring occasionally, until softened and starting to turn a deep brown, anywhere from 45-60 minutes. The amount of time it takes to really caramelize the onions can depend on the size and type of your pot and the heat used, but it is best to take your time and use a lower heat so you don't burn the onions. If they seem to be burning, reduce the heat slightly, be sure to stir them well, and add a splash of water or beef broth. The onions should be caramelized to a deep, rich brown color.
While the onions cook, preheat oven to 400°F. Arrange sliced baguette pieces on a baking sheet. Once the oven is hot, toast the bread for 8-10 minutes until lightly golden and crisp.
Once the onions are fully caramelized, sprinkle the flour over them onions and stir well until the flour has been absorbed, about 30-60 seconds.
Add the ½ cup of white wine (or just ½ cup of the beef broth, if you want to make this french onion soup recipe without wine) and increase the heat to high heat. Use a wooden spoon to deglaze the bottom of the pot by scraping up any browned bits (called fond, which gives loads of flavor) until the onions are almost jam-like in consistency. Continue to cook until the wine has completely cooked down and evaporated to the point that there is no more liquid in the pot.
Add beef broth garlic, bay leaves, thyme, salt, and pepper. Stir well, then bring to a boil.
Once boiling, cover the pot with a lid. Reduce the heat to low and simmer for 20 minutes.
Set 6 oven-safe bowls on a baking sheet. Ladle the hot soup into the bowls, evenly distributing it, then cover each bowl of soup with slices of baguette, making sure they don't overlap. Sprinkle a generous amount of the gruyere and freshly grated Parmigiano Reggiano cheeses on top of the bread slices in each bowl.
Turn on the oven broiler and carefully transfer the baking sheet with the soup bowls to the oven under the broiler. Broil just until the cheese is melted and starts to bubble and toast. Serve immediately.

Notes

Onions: Vidalia onions or sweet onions work best, although you can also use yellow onions.
Cheese: Choose a cheese with good melting properties. Gruyère and Swiss cheese are popular choices for French Onion Soup due to their melting qualities and complementary flavors, but provolone, mozzarella cheese, or even monterey jack can all work well.
Make-Ahead: The soup broth can be made up to 3 days ahead and refrigerated, then reheated before adding the toasted baguette and cheese.
Freezing: You can freeze the soup for up to 3 months. Thaw, reheat, then add the sliced baguette and cheese.
Without wine: If making this recipe without wine, I also recommend adding 1 ½ Tablespoons balsamic vinegar for more body and flavor.

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