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Cheesy French Onion Soup

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Our French Onion Soup is made from sweet caramelized onions in a flavorful beef broth then topped with toasted slices of French baguette and both Gruyere and Emmentaler shredded cheese.
Servings: 4
Total Time: 1 hour 50 minutes
bowl of french onion soup topped with crusty bread and shredded cheese

French onion soup is a bowl of sweet soft caramelized onions in a flavorful beef broth topped with gooey cheese melting into toasted slices of French bread.

bowl of french onion soup topped with crusty bread and shredded cheese

While our recipe for classic French onion soup is easy, it is nonetheless time-consuming. You’ll find it is worth every spoonful, however.

Key Ingredients and Substitutions


To make this delicious French onion soup you really only need a shortlist of easy-to-find ingredients, most of which you probably already have in your pantry or refrigerator.

ingredients for french onion soup
  • Onions are the star of this dish and we have an entire blog post dedicated to selecting and then caramelizing onions. You can use any onion but just note there will be differing levels of sweetness from the chosen variety. White onions will be sweet and mild. Red onions stronger onion flavor, are slightly bitter, and not as sweet. Yellow onions are our favorite French Onion soup. They are nice and mild with a naturally occurring sweetness you want for caramelized onions.
  • Butter & Olive Oil are our go-to choices of fat for this recipe but you can substitute the olive oil for just butter. We always use and recommend unsalted butter so that you are only adding the amount of salt you want or the recipe calls for.
  • Beef stock is the classic base but you can easily switch it out for vegetable stock to make this a vegetarian version. Chicken stock will also work if that is all you have on hand. As with any substitution, the final flavor will be different but still delicious.
  • Dry Vermouth adds an earthy, herbal flavor to the soup and is completely optional. You can add a tablespoon of Worcestershire to give it some additional depth of flavor instead.
  • Thyme sprigs and bay leaf are the only two “herbs” that you need for this recipe. We prefer to use fresh thyme sprigs but you can substitute with ground thyme. Typically one large sprig of thyme is equivalent to 1/4 teaspoon of dry thyme.
  • French baguette is the classic bread of choice for this recipe but any bread that has a crispy crust can be used.
  • Cheese is the final key ingredient. We use a combo of Gruyere and Emmentaler which are both types of Swiss cheeses. Gruyere is slightly less fatty than Emmentaler, which is why we use a combo, but you can use any type of Swiss cheese. The key is selecting a cheese that melts easily without breaking into liquid fat and milk solids.

How to Make French Onion Soup


Here are the quick step-by-step instructions with visuals; you can find the full instructions with the exact ingredients in the recipe card below.
This post may contain paid affiliate sales links. As an Amazon Associate, I earn from qualifying purchases. Please see my full disclaimer policy for details.

Pro-tip: Make a little extra soup as it freezes well. Defrost and top with some toasted slices of your favorite crusty bread and cheese for an easy weeknight soup dinner.

Caramelizing Onions

process shots of steps 1 and 2 for how to make caramelized onions

1. Prep and Soften the Onions: Rough chop onions so that slices are between ⅛ and ¼ inches thick. Heat the butter and olive oil in a saucepan on medium heat. Once the butter has melted add onions and sweat them until they become translucent.

2. Caramelize the Onions: Reduce heat to low and continue to cook onions, stirring every 5-10 minutes to prevent them from sticking. Deglaze pan with water or chicken stock when fond starts to form on the pan. As the onions further caramelize, continue stirring every 5-10 minutes and deglazing the saucepan as fond forms. When the onions achieve a blonde color they are the perfect texture for French Onion Soup.

French Onion Soup

Cheesy French Onion Soup Process Shots for Steps 1-2

1. Prep the Soup: Once the onions have cooked, add 4 cups of beef broth, thyme, and bay leaf. Bring soup to a boil, and then reduce heat. Partially cover with a lid and simmer for 20 minutes. Season with salt to taste

2. Top with Bread and Cheese: Place 4 oven/broiler-safe soup bowls on a cookie or baking sheet. Fill each of the soup bowls with the soup and then top with two slices of French baguette and ½ cup of shredded cheese. Broil until the cheese is melted and begins to brown.

french onion served in a bowl with crusty bread and shredded cheese

Frequently Asked Questions


Can I Freeze French Onion Soup?

Yes! Once the soup has cooled store it in a freezer-safe container or gallons size freezer bag. Freeze bags are my preference since they can be placed flat in the freezer and stacked. The soup can be frozen for up to 3 months. When ready to reheat, just thaw it overnight in the refrigerator and then heat it in a saucepan on the stove until warmed through. Then top with slices of baguette and shredded cheese and broil until cheese has melted.
Note: It is best to freeze soup prior to topping it with bread and cheese.

Can I make French Onion Soup ahead of time?

Yes! You can make the soup part of this recipe up to 2 days ahead. Refrigerate it in an airtight container until ready to use. When you are ready to serve, reheat it in a saucepan on the stove until warm. Top with slices of baguette and shredded cheese and broil until cheese has melted.

bowl of french onion soup topped with melty cheese and slices of baguette

More Soup Recipes to Try


Looking for more inspired comforting soup recipes? Try these other favorites:

  • Italian Sausage Gnocchi Soup – This 30-minute one-pot soup is made from canned tomatoes, packaged gnocchi, and sausage and makes the perfect weeknight meal.
  • Pork Pozole Verde – A traditional Mexican comfort food with a New Mexico twist. Made with grilled pork, tomatillo, and hatch peppers, this is a robust soup that borders on a stew.
  • Rotisserie Chicken Tortilla Soup – Ready in 30 minutes this soup is flavorful, quick, and perfect for leftovers. Made from tender rotisserie chicken, black beans, corn, and spices in a smoky tomato broth. Top with crispy tortillas and lime for a delicious weeknight dinner.

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bowl of french onion soup topped with crusty bread and shredded cheese

Cheesy French Onion Soup

Posted by Melissa
Our French Onion Soup is made from sweet caramelized onions in a flavorful beef broth then topped with toasted slices of French baguette and both Gruyere and Emmentaler shredded cheese.
5 from 2 votes

This recipe may contain paid affiliate sales links. As an Amazon Associate, I earn from qualifying purchases. Please see my full disclaimer policy for details.

Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 50 minutes
Course Soup
Cuisine French
Servings 4
Calories 599 kcal

Equipment

Ingredients  

Caramelized Onions

  • 3 large peeled sweet or yellow onions, (about 1.5 pounds)
  • 2 tablespoons olive oil
  • 2 tablespoons unsalted butter
  • 1 ½ cups water or beef stock

French Onion Soup

  • 4 cups beef broth
  • 2 tablespoon dry vermouth optional
  • 4 springs thyme
  • 1 bay leaf
  • salt to taste
  • 8 slices baguette approximately 1 inch thick
  • 1 cup Gruyere cheese shredded
  • 1 cup Emmentaler cheese shredded

Instructions 

Caramelized Onions

  • Rough chop onions so that slices are between ⅛ and ¼ inches thick.
  • Heat the butter and olive oil in a saucepan on medium heat. Once the butter has melted add onions and sweat them until they become translucent.
  • Reduce heat to low and continue to cook onions, stirring every 5-10 minutes to prevent them from sticking. Deglaze pan with water or stock when fond starts to form on the pan.
  • As onions continue to caramelize, continue stirring every 5-10 minutes and deglazing the saucepan as fond forms.
  • Continue cooking until onions have reached a deep blonde color.

French Onion Soup

  • Once onions have cooked, add 4 cups of beef broth, dry vermouth, thyme, and bay leaf.
  • Bring soup to a boil, and then reduce heat.
  • Partially cover with a lid and simmer for 20 minutes. Season with salt to taste
  • Combine Gruyere and Emmentaler cheese in a medium bowl, set aside.
  • Place 4 oven/broiler-safe soup bowls on a cookie or baking sheet.
  • Fill each of the soup bowls with the soup and then top with two slices of french baguette and ½ cup of shredded cheese.
  • Broil until the cheese is melted and begins to brown.

Notes

1. Caramelized Onions: You can make the caramelized onions in advance. They can be frozen in an airtight container for up to 3 months or refrigerated for up to 3 days.
2.  Dry Vermouth: Other types of alcohol can be substituted for dry vermouth such as sherry, white wine, or brandy. You can also omit it and use a tablespoon of Worcestershire sauce for additional depth of flavor.
3. Beef Stock: This recipe can be made vegetarian by substituting vegetable stock for beef stock.  
4. French Baguette: Any type of artisan bread can be substituted but the best bread will be crusty to hold up to the cheese and delicious onion soup.
5. Cheese: Any good swiss cheese can be substituted for the gruyere and Emmentaler cheese or you can double up on gruyere and omit the Emmentaler.
6. Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed. The nutritional value is only for the French onion soup and will vary and does not include the nutritional value of any toppings. It does not include the nutrition for any substitutions.
7. Be sure to check out the Key Ingredients along with the Recipe Tips and Notes sections found in the post, for more tips, options, substitutions, and variations for this recipe! You will also find step-by-step photos there.

Nutrition

Serving: 1 servingCalories: 599 kcalCarbohydrates: 54 gProtein: 29 gFat: 30 gSaturated Fat: 10 gPolyunsaturated Fat: 2 gMonounsaturated Fat: 9 gCholesterol: 49 mgSodium: 595 mgPotassium: 592 mgFiber: 5 gSugar: 9 gVitamin A: 28 IUVitamin C: 53 mgCalcium: 49 mgIron: 23 mg
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