This recipe for vegetarian French onion soup has all of the delicious savory flavors of the traditional version. Sweet caramelized onions, melty Gruyere cheese, and crusty whole grain French bread…nothing more comforting on a cold day!
French onion soup has always been a favorite of mine, especially during the holidays. But, most of the beef broth/stock found on grocery store shelves contains unnecessary ingredients that I do not want in my body, like “caramel coloring”. And although I make my own chicken bone broth frequently, I never make beef bone broth because we rarely have beef bones.
So I came up with a vegetarian French onion soup recipe using mushroom broth! My vegetarian daughter was thrilled. Mushroom broth is anti-inflammatory, boosts the immune system, is good for gut health, and remineralizes the body. Plus, it has a rich, savory flavor, and it’s easy to find good quality versions on grocery store shelves. Hooray! Of course, if you have access to a high-quality beef broth/stock, you can definitely use it in this recipe!
The Onions
This recipe is easy to make, but it does take some time. It’s important to cook the onions slowly so they caramelize which takes about 35 minutes. They should be a deep color which gives the soup its rich flavor. I like to use a combination of yellow and sweet onions, but you can use either.
Bouquet Garni
A bouquet garni is French for “garnished bouquet” and is a bundle of herbs either tied together or placed in a cheesecloth. For this recipe, I use 2 cloves of garlic, basil, a few peppercorns, thyme, bay leaf, and oregano. I place all of the herbs in a piece of cheesecloth and tie it together. Once the onions are caramelized you will add them to your broth and simmer it with the bouquet garni for 30 minutes.
The Cheese
Gruyere cheese is a nutty melty cheese that originated in Switzerland and is named after the town of Gruyeres. It has a sweet and slightly salty flavor and is my favorite cheese to use in French onion soup. Emmentaler or Swiss can be used if you cannot find Gruyere.
This soup is hearty and can be served as a main meal by itself or with a side salad. So yummy and totally worth every minute it takes to make it! Enjoy!

Vegetarian French Onion Soup
Sweet caramelized onions, melty Gruyere cheese, and crusty whole grain French bread...nothing more comforting on a cold day!
Ingredients
- 3 lbs yellow and/or sweet onions, sliced I like to use a combination of the two.
- 3 tbsp butter
- 1 cup dry white wine
- 6 cups mushroom broth or high-quality beef stock
- 1 bouquet garni - 2 cloves of garlic, 2 bay leaves, a few peppercorns, fresh basil, thyme, and oregano
- salt and pepper to taste
- 1 cup Gruyere cheese, grated
- 1 whole grain baguette, sliced and toasted
Instructions
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Melt butter in a large pot over medium heat. Add onions and cook over medium-low heat, stirring often, until they have softened and are caramelized about 35 minutes. Do not allow onions to burn.
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Pour in wine and scrape any brown bits from the bottom of the pot. Cook 6 minutes over medium-high heat.
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Stir in mushroom broth or beef stock and bouquet garni. Season with salt and pepper. Cook over medium heat for 30 minutes stirring occasionally. Do not cover.
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Preheat oven to broil.
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Place 2 tablespoons of grated cheese in the bottom of 4 ovenproof bowls. Divide soup evenly into bowls. Top with toasted baguette slices and sprinkle with remaining cheese.
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Set bowls on baking sheet and place in middle of oven. Broil until cheese has melted and is golden brown. Be sure to watch carefully. Serve immediately. Enjoy!
Recipe Notes
We recommend using organic ingredients whenever possible.
Here are some of my other favorite soups!
Molly says
Oh I love French onion soup…next cold snap I’ll have to try it. Question can I freeze it? I think I’ll be the only one eating it here.
smallgesturesmatter@gmail.com says
Great question Molly! Yes, you can freeze it. Freeze it before you add the bread and cheese. When you are ready to eat it, heat it up and then add the cheese and bread and broil.