French Onion Soup

French onion soup in a ramekin with a spoon

This easy French onion soup recipe is made with perfectly caramelized onions and a few other simple ingredients. It’s full of flavor and one of the coziest cool-weather meals around!


  • 3 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 5 large yellow Vidalia onions, peeled and thinly sliced
  • 1 teaspoon kosher salt, plus more to taste
  • 1 cup dry white wine
  • 1 tablespoon all-purpose flour
  • 67 cups vegetable broth, according to your preference
  • 1 tablespoon sherry vinegar
  • ½ teaspoon black pepper, more to taste
  • French bread cut into slices
  • 46 slices swiss cheese


Caramelize the onions. Melt the butter in a large heavy pot over medium heat. Add oil and the sliced onions and 1 teaspoon of kosher salt. Stir frequently and cook for about 5 minutes, giving the onions time to soften. Reduce the heat to medium-low and continue cooking, stirring often, until the onions are a light golden color. This will take about 60 minutes. 

Add wine and flour. When the onions have finished caramelizing, add the wine and bring the mixture to a simmer. Add the flour and mix well, stirring constantly for a couple of minutes until the mixture thickens. Scrape the bottom of your pot to get all the flavorful bits that have stuck there.

Add broth, vinegar and pepper. Pour the broth into the pot, stirring as you add it to make sure it is well incorporated. Stir in the sherry vinegar. Taste and season with black pepper. You can add more salt if needed at this point.

Cook the soup. Simmer over medium-low heat for 30 minutes, stirring often.

Toast the bread. While the soup is simmering, slice your french bread and lightly toast the pieces in your toaster oven.

Add the bread and cheese. Ladle the soup into oven-proof single-serving bowls and place the bowls on a baking sheet, which makes it easier to get them in and out of the oven. Top each bowl with a slice of toasted french bread and then a slice or two of swiss cheese. You can also use shredded Gruyere cheese.

Broil. Place the bowls in the oven and turn on the broiler. Broil for 1-2 minutes, until the cheese melts. Keep an eye on it so that the cheese doesn’t burn! 

Serve. Remove the bowls from the oven and with oven mitts carefully move the hot bowls to serving plates. Dig in!

Keywords: french onion soup recipe, easy french onion soup, vegetarian french onion soup