How to Make Classic French Onion Soup

This how to make French Onion Soup recipe and guide will teach you everything you need to know to make the best French Onion Soup at home.

Learn everything from how to caramelize onions (with a huge time-saving tip), key ingredients and why you use them, as well as general tips for the best classic french onion soup recipe. Plus how to make it gluten-free and/or vegan.

French onion soup is a classic recipe that can elevate any meal. It’s simple to make and loaded with flavor. While caramelizing onions takes time, it’s very easy and requires little hands-on time. It’s a key element in this soup for good reason.

This French Onion Soup is restaurant quality with the ease and convenience of home-cooking. Try it as a side to other comfort food dishes such as roasted meats.

Ingredients in French Onion Soup

• Yellow onions: Use lots of caramelized onions as a key ingredient
• Butter and olive oil: Cooked with onions to add flavor
• All-purpose flour: Along with butter, it helps create a roux and thickens the broth
• Dry vermouth or white wine: Deglazes pan and enhances flavors of the broth
• Beef broth: The main base for French onion soup
• Worchestire sauce: Has umami effect and enhances flavors
• Italian seasoning and ground black pepper: Adds additional flavor
• Sliced bread or croutons: Toasted and tops the soup
• Finely shredded cheese: Sprinkled on top and melted until bubbly. Gruyère cheese is recommended.
• Fresh parsley: Garnish that adds flavor and color

Pro tip: I recommend organic and regular (non-reduced) sodium beef broth for best flavor. Depending on sodium content of the broth, add more or less salt to soup to reach desired flavor.

How to make French Onion Soup

1. Peel and thinly slice yellow onions. Note: yellow onions are best for flavor as they will be sweeter than white or red onions.
2. Melt butter with olive oil a large pot over medium heat. Stir in onions and cook 15 minutes, stirring often.
3. Reduce heat to medium-low and cook onions 45 minutes to 1 hour more, stirring every 5-10 minutes. They should turn a deep golden brown from caramelization, not burning.
4. Turn heat up to medium-high and stir in flour. Cook 1 minute, then stir in dry vermouth and cook 2-3 minutes more until evaporated.
5. Stir in beef broth, Worcheshire sauce, Italian seasoning, and pepper. Bring to a low boil then reduce heat to medium-low. Simmer at least 20 minutes.
6. Spoon into oven-safe bowls or ramekins and place them on a baking sheet. Top each French onion soup bowl with a slice of bread or croutons and generously sprinkle with cheese.
7. Broil in oven for 3-4 minutes until bread is browned and cheese is melted. Remove from oven and let bowls cool slightly. Serve garnished with parsley.

How to caramelize onions

Thinly slice 6 medium yellow onions. Melt butter and olive oil in a pan over medium heat. Stir in onions and cook 15 minutes, stirring often. Reduce heat to medium-low and cook 45-60 minutes more, stirring every 5-10 minutes until deep golden brown.

Tips for caramelizing onions

• Thinly slicing onions creates more surface area for browning. It also provides better texture for French onion soup. Use yellow onions for sweetness and best flavor.
• Pro tip: To save a bunch of time, run onion halves through a food processor with slicer attachment. You can slice all onions in less than 5 minutes.
• Cook in a bit of melted butter and olive oil to prevent sticking and enhance flavors
• Start with medium heat to soften onions and speed up the process
• Cook for the remainder of time on medium-low to prevent burning. Reduce heat or stir more often if onions start to burn.
• Slow is better: The browning comes from the slow caramelization process, not burning. This makes onions soft, tender and sweet.

How to make French Onion Soup easy

Most of the work comes from slicing a large number of onions. To save time, run onion halves through a food processor with slicer attachment. You can slice all onions in just a few minutes.

Carmalizing onions may seem daunting but can be very easy, especially if you use low heat and longer cooking time. Read tips below for perfectly caramelized onions.

After that simply combine remaining ingredients in a large pot and simmer until thickened slightly.

How to make French Onion Soup gluten-free

Omit the flour, but the broth won’t be as thick. For a thicker broth, try substituting with arrowroot flour or 1-tablespoon cornstarch mixed in a bit of water. 

Note: Add the cornstarch later to the broth, instead of earlier to the caramelized onions. Cornstarch works best in heated liquids. Stir often until simmering to prevent clumping. 

Also be sure the other ingredients you use contain no gluten, such as the beef broth. You can omit the bread topping, but this is a classic addition to French onion soup. Instead, substitute with your favorite gluten-free bread. 

How to make French Onion Soup vegan or vegetarian

French onion soup most commonly uses beef broth, for vegan use vegetable stock instead. Replace butter with extra olive oil when cooking onions. Omit cheese topping or use vegan cheese.

Serving suggestion for this soup

The most classic way to serve is in an oven-safe bowl topped with sliced bread and melted cheese. You could also use croutons topped with melted cheese and a unique alternative and extra crunch. Another touch is to add fresh parsley leaves as garnish.

How long can French Onion Soup be stored?

• Bring soup without bread and cheese topping close to room temp, then place in sealed container. The soup can be stored in the fridge up to a week.
• To freeze, place cooled soup in smaller containers or freezer bags and store in freezer up to 4-6 months.
• To serve leftovers: Defrost in the fridge if frozen. Microwave or heat in a pot over medium heat. Place soup in oven safe bowls and top with bread and cheese. Broil until melted then serve.

Classic French Onion Soup recipe at-a-glance

Flavor profiles: Rich, savory and bursting with sweet caramelized onion flavor.
Texture: Soft, moist and super chewy.
Dietary Options/Substitutions: Use low-sodium beef broth to reduce sodium content. Omit flour or substitute with 1-tablespoon cornstarch in water for gluten-free. For vegan use vegetable stock instead of beef stock, olive oil instead of butter, and vegan cheese.

More Delicious Soup Recipes You Might Like:

• Easy Slow Cooker Chicken Pho Soup
• Italian One Pot Cod Fish Soup
• One Pot Chicken Minestrone Soup

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5 from 16 votes

Classic French Onion Soup

Easy homemade soup loaded with sweet caramelized onion flavor, beef broth and seasonings, topped with toasted bread and melted cheese. 

Course Soup

Cuisine French

Keyword French onion soup, homemade French onion soup, how to make French onion soup

Prep Time 10 minutes minutes

Cook Time 1 hour hour 20 minutes minutes

Total Time 1 hour hour 30 minutes minutes

Calories 320kcal

Servings 6

Author: Matt Ivan

Did you know? Servings and ingredient amounts can be adjusted on all my recipes. Click the green number above to change.

Ingredients

• ▢ 6 medium yellow onions
• ▢ 2 tablespoons butter
• ▢ 2 tablespoons light olive oil
• ▢ 3 tablespoons all-purpose flour
• ▢ ¼ cup dry vermouth, or white wine
• ▢ 8 cups beef broth
• ▢ 1 tablespoon Worchestire sauce
• ▢ ½ tablespoon Italian seasoning
• ▢ ½ teaspoon ground black pepper
• ▢ Salt to taste
• ▢ 6 slices bread, or croutons
• ▢ 1 cup finely shredded Gruyère cheese
• ▢ Fresh parsley, as garnish

Instructions

• Peel and thinly slice onions. Pro Tip: Use a food processor with slice attachment to speed this up. You should have about 6 cups of sliced onions.
• Melt butter with olive oil a large pot over medium heat. Stir in onions and cook 15 minutes, stirring often.
• Reduce heat to medium-low and cook onions 45 minutes to 1 hour more, stirring every 5-10 minutes. Reduce heat or stir more often if they start to burn. Onions should turn a deep golden brown from caramelization, not burning.
• Turn heat up to medium-high and stir in flour. Cook 1 minute, then stir in vermouth and cook 2-3 minutes more until evaporated.
• Stir in beef broth, Worcheshire sauce, Italian seasoning, and pepper. Bring to a low boil then reduce heat to medium-low. Simmer at least 20 minutes.
• Optional: Stir in desired amount of salt, just a little bit at a time, until desired flavor is reached.  
• Spoon into oven-safe bowls and place them on a baking sheet. Top each bowl with a slice of bread or a few croutons and generously sprinkle with cheese.
• Broil in oven for 3-4 minutes until bread is browned and cheese is melted. Remove from oven and let bowls cool slightly. Serve garnished with parsley.

Notes

• Use yellow onions for best flavor and sweetness
• Thinly slicing onions creates more surface area for browning. It also provides better texture for the French onion soup.
• Use organic and regular (non-reduced) sodium beef broth for best flavor. Depending on sodium content of the broth, add more or less salt to soup to reach desired flavor.
• Dietary Options/Substitutions: Use low-sodium beef broth to reduce sodium content. Omit flour or substitute with 1-tablespoon cornstarch in water for gluten-free (add cornstarch later to broth and stir constantly until simmering, instead of earlier with caramelized onions). For vegan use vegetable stock instead of beef stock, olive oil instead of butter, and vegan cheese.
• If you don't have dry vermouth, white cooking wine works well. Omit either if you don't want to use alcohol.
• Use the desired amount of shredded cheese on top. A generous coating will create a nice layer of gooey cheese.
• For leftovers: Bring close to room temp, then place in sealed container. The soup can be stored in the fridge up to a week.
• To freeze, place cooled soup in smaller containers or freezer bags and store in freezer up to 4-6 months.
• To serve leftovers: Defrost in the fridge if frozen. Microwave or heat in a pot over medium heat. Place soup in oven safe bowls and top with bread and cheese. Broil until melted then serve.

Nutrition Facts

Classic French Onion Soup

Amount Per Serving

Calories 320 Calories from Fat 144

% Daily Value*

Fat 16g25%

Saturated Fat 7g44%

Cholesterol 29mg10%

Sodium 1518mg66%

Potassium 425mg12%

Carbohydrates 28g9%

Fiber 3g13%

Sugar 6g7%

Protein 12g24%

Vitamin A 305IU6%

Vitamin C 8.5mg10%

Calcium 229mg23%

Iron 2.4mg13%

* Percent Daily Values are based on a 2000 calorie diet.

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