Gluten Free French Onion Soup: A Restaurant Favorite from Your Kitchen

Do you miss ordering French Onion Soup in a restaurant?  I did until I learned that it's easy to make my own homemade gluten-free French Onion Soup.

About Traditional French Onion Soup

Is French Onion Soup Gluten-Free?

There are a few places that classic French onion soup recipes can trip you up when it comes to gluten.  The first is the most obvious and that's the chunk of crispy French baguette that floats on top, covered in melted cheese.  But making gluten free onion soup isn't as simple as leaving off the bread or substituting for gluten-free bread.  And this my friends is why you and I cannot order French onion soup in a restaurant.  

It's More Than Just the Bread

Traditional French onion soup is made from a roux, which is a fancy, cheffy term for thickening with flour and fat.  So even if you ask your waiter to leave off the bread, chances are the onion soup you're ordering will still not be gluten-free. 

The third troublesome French onion soup ingredient is the beef broth.  It's kind of hit and miss here as some commercial stocks or broths are gluten-free and some aren't.  When it comes to ordering in a restaurant, you just can't be sure.  Unless of course you ask, and we know when it comes to restaurant dining we should always ask lots of questions. 

French Onion Soup Ingredients

The Onions

The recipe calls for 3 pounds of onions.  Does it matter what kind of onions you ask.  Well no, not really.  But I do have favorites.

We tend to think of French onion soup as something fancy that we order in a restaurant, but it started out much more humbly. It was a staple in poor households in France who didn't have a lot of variety in their food choices, but always had lots of onions.  So when you think of this this way, its a good way to use up those onions in your pantry before they go bad, no matter what kind of onions they are.

If you're buying onions for French onion soup, include a couple of red onions and a big sweet onion.  The flavors are just a bit different and will give your finished soup a little extra depth and je ne sais quoi

Pro Tip - Slicing onions for French onion soup: 

  • This is a lot of onion, so use a mandolin if you have one.  If not a good chefs knife is fine. 

To reduce the tears:

  • Use a sharp knife, this will reduce the amount of onion juice flying around. 
  • Be a mouth breather.  The sensors that cause the tears are in your nose so if you breath through your mouth it will help.

Beef Stock

If you make your own gluten-free stock that's great.  I like to when I have time, but ready made beef stock is fine.  Just be sure to read that ingredients so you know it's gluten free. A lot of commercial stocks contain barley malt so you really need to be careful.  You can also use chicken or vegetable stock but the broth won't be as dark.

Cognac or Brandy

This is a classic French onion soup ingredient and if you have it in your liquor cabinet, perfect! Use it.  If not I don't want you going out to spend money on this when there are cheaper alternatives.  Use a tablespoon of gluten-free Worcestershire sauce and 2 teaspoons of sherry or wine vinegar.  This will impart loads of flavor and that little acidic snap you're looking for. 

The Cheese

The best cheese for French onion soup, or a least the one that is traditionally used is Gruyère, sometimes with a little parmesan sprinkled on top for a stronger cheesy flavor and a bit of texture. .  But really, you can use whatever you like.  It's the stretchiness of the Gruyère that makes it so tantalizing and perfect for this soup, but you could also use mozzarella.  If you have issues with cows milk you can use goat mozzarella with a little Pecorino Romano.  If you're making vegan French onion soup then vegan cheese works great. 


The very first onion soup I made from my Martha Stewart cookbook didn't have any herbs, but I've made this gluten-free French onion soup so many times with the thyme and bay leaves that I know it wouldn't be the same without them.  I do highly recommend adding these in.  Fresh thyme is best but if you don't have it, a teaspoon of dried thyme will work. 

The photo shows the herbs on a piece of cheesecloth with some string.  If you gather up the cheese cloth around the herbs and tie it with the string to make a "spice bag", you don't have to worry about digging out the bay leaves and thyme stems later. 

Can I Make Vegan French Onion Soup

Of course you can.  You can do anything you want and I would be the last to stand in your way.  Gluten-free French onion soup is actually perfect for converting to a vegan recipe.  Simply substitute the beef stock for vegetable stock, butter for margarine and top with vegan cheese.  The broth will be a bit lighter in color but you'll still get that beautiful umami flavor from all those deeply caramelized onions.  So go for it.  It will be great. 

Can I Freeze French Onion Soup?

Absolutely!  I like to freeze soups in individual serving sizes in Ziploc bags.  Ladle a cupful of soup (or a little more) into each of several Ziploc bags then lay them out flat on a baking sheet.  Put them in the freezer like that and when they are frozen you can take them off the baking sheet and easily stack them.  The won't take up much space at all.

When you're ready to serve, remove your individual serving of frozen French onion soup from the bag and put it either in a small pot on the stove or in a bowl to heat in the microwave.  Then add your bread and cheese and enjoy!

Making Gluten-Free French Onion Soup

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Pin Image - bowl of Gluten Free French Onion Soup with melted cheese

There are two ways to do this, both are equally amazing.  You can make traditional French onion soup on the stove top, or you can make crockpot French onion soup.  The steps are the same:

  1. Caramelize the onions
  2. Add the remaining ingredients
  3. Simmer the soup

The techniques differ a bit and the timing differs a lot.

Stovetop French Onion Soup

This is certainly the quickest of the two methods, but also the most hands on.  You'll be 1 1/2 to 2 hours including caramelizing the onions and simmering the soup.  But you'll need to keep an eye especially during the caramelizing phase so your onions don't burn.

Caramelizing the Onions

This is the most important step and the one that you (and I) are most likely to mess up.  You don't want to burn your onions!

Start by melting the butter on med-high heat in the bottom of your soup pot or Dutch oven.  Add the onions and sprinkle with sugar.  The sugar helps get the caramelization started.  It will seem like a lot of onions, but they will cook down.  Stir occasionally to keep from burning and to coat the onions in the butter.  When they are kind of translucent, about 15 min, turn the heat down to medium and continue to cook until the onions are brown and sticky, 35 to 40 minutes.  Keep a close eye and stir frequently to keep them from burning.  If they are cooking too slow turn the heat up a bit.  If they are cooking too fast then turn it down.  If you're having trouble with the onions sticking to the bottom of the pot you can add a tablespoon of water. 

Finishing the Soup

Sprinkle the gluten-free flour over the onions, stir, then stir in the wine and cognac. 

Add the beef stock and herbs and simmer covered for about 1/2 hour.  You can leave it to simmer longer if you like.  More is better to let the flavors get to know each other.  You just don't want to cook it so long that the onions disintegrate.

Add salt and pepper to taste.

Crockpot French Onion Soup

There are two main differences between this and the stovetop method.

1.  The caramelization takes longer but is less hands on.  You can do it overnight if you like.

2. You can leave out the flour.  I think it's because the onions cook so slow that the soup thickens up beautifully on its own, so no gluten-free flour is necessary. 

I totally recommend starting this the night before if you're cooking on the low setting on your crockpot because you'll be about 20 hours start to finish.  It will be about 12 - 14 hours on high.

Caramelizing the Onions

Add the onions to the crockpot, stir in the butter, sugar and cognac (or gluten-free Worcestershire and wine vinegar if using instead) and a little salt.

Cover and cook on high for 8-9 hours or on low for 12 - 14.  Stir a few times (2 or 3) to keep from burning.

How many times you need to stir will depend a bit on your crockpot.  Keep in mind that each time you lift the lid, you're losing cooking time.  That's why most slow cooker recipes recommend you don't lift the lid at all during cooking if possible.  With these onions however, you don't have much moisture, if you did they wouldn't brown, and onions believe it or not have a fair bit of sugar.  So there is a risk of burning.  Try dividing the cooking time by 3, so that's between 4 and 5.  Plan to give your onions a stir about every 4 to 5 hours.  If you start them before bed this may mean getting up in the night, or if you want to chance leaving them a little longer then get up bright and early.  It's commitment to a soup for sure, but it will be worth it. 

Finishing the Soup

Simply add the beef stock, wine and the herbs and cook on high for 2-3 hours or on low 4-5 hours.

Add salt and pepper to taste.

Serving Gluten-Free French Onion Soup

This is an amazing dish to serve to guests.  You can even make it ahead to ease up the burden of cooking on the day of your gathering.   Then just heat it up before you're ready to serve it.

Heat up the broiler in your oven.

Ladle the soup into individual ramekins or French onion soup bowls then float a slice of toasted crusty gluten-free baguette on top.  You can also make gluten-free toast and cut a round shape with a biscuit cutter or aluminum can.  Spread a little butter on it and it will be perfect. 

Sprinkle a generous amount of grated cheese on top and place the bowls all on a baking tray.  Slide them into the oven under the broiler to brown and melt the cheese, about 2 minutes.  Keep a close eye, you don't want to burn your cheese. 

Gluten-Free French Onion Soup Recipe

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Gluten Free French Onion Soup: A Restaurant Favorite from Your Kitchen

By ,

French onion soup, overhead shot with cheese, onion and garlic

Do you miss ordering French Onion Soup in a restaurant? I did until I learned that it's easy to make my own homemade gluten-free French Onion Soup.

Prep Time: 20 minutes
Cook time: 90 minutes
Yield: 8 to 10 servings
Tags: Gluten Free, Vegan Option, Keto Option


  • 3 lbs of onions (about 5 - 7 depending on size)
  • 4 tbsp butter or margarine
  • 2 tsp brown sugar
  • 1 tbsp gluten free all purpose flour (for stovetop method only)
  • ¼ cup white wine
  • 3 tbsp cognac or brandy (or subst. 1 tbsp. gluten-free Worcestershire and 2 tsp sherry or wine vinegar)
  • 5 sprigs fresh thyme
  • 3 bay leaves
  • 6 cups beef stock
  • Gluten free baguette or toast
  • 2 cups cheese grated or thinly sliced – try mozzarella, gruyere, or emmental with a little parmigiana Reggiano to sprinkle on top.


Method 1 - Stovetop French Onion Soup

  1. Melt the butter in the bottom of a large soup pot or Dutch oven.

  2. Add the onions and sprinkle with sugar. Cook until the onions are translucent stirring occasionally to keep from burning. About 15 min.

  3. Turn heat down to medium and cook until onions are deep brown and sticky, 35 - 40 min. Keep and eye and stir frequently. Add a tbsp. of water if necessary to prevent sticking.

  4. Sprinkle with gluten-free flour, stir.

  5. Add wine and cognac, stir.

  6. Add beef stock, thyme, bay leaves and lightly season with salt and pepper.

  7. Cover and simmer for about 1/2 hour. Longer is fine.

  8. Adjust the seasoning if necessary.

  9. Ladle into oven safe bowls, add a slice of toasted gluten-free baguette or toast cut into a round shape, top with cheese and melt under the broiler.

Method 2 - Crockpot French Onion Soup

  • Add the sliced onions to the crockpot with the butter, brown sugar, cognac or vinegar and gluten-free Worcestershire if using, and a bit of salt.

  • Cover and cook on high for 8-9 hours or on low for 12 - 14. Stir a few times (2 or 3) to keep from burning.

  • Add the beef stock, wine and the herbs and cook on high for 2-3 hours or on low 4-5 hours.

  • Adjust the seasoning if necessary.

  • Ladle into oven safe bowls, add a slice of toasted gluten-free baguette or toast cut into a round shape, top with cheese and melt under the broiler.

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