French keto onion soup is a low-carb version of the traditional classic French onion soup recipe. Sweet caramelized onion simmered into a beef broth with cheesy keto bread croutons topped with French swiss cheese.
Can I have French onion soup on keto?
No, you can’t! Traditional French onion soup has many high-carb ingredients. But wait! I have created a 100% keto-friendly French onion soup!
As a French girl on a keto diet, I love French onion soup so I had to recreate a keto version of my family traditional French onion soup recipe!
Is French onion soup keto?
If you wonder is French onion soup keto-friendly? Well, no! A traditional French onion soup is not keto-approved. Below I listed all the ingredients and reasons why you shouldn’t eat a traditional French onion soup on keto:.
Sugar. a classic French onion soup requires onions that are caramelized in sugar. Sugar is your worst enemy on keto since it is pure carbs. Only 10 grams is 10 grams of net carbs!
White wheat flour. this is used to help thicken the soup and like sugar, flour is pure carbs, so not for you on keto!
White wine. White wine is used to deglaze the onions. You can have some dry white wine on keto if used with moderation but unfortunately, the classic French onion soup uses quite a good amount which brings the carbs very high.
Croutons. a classic French onion soup is always topped with lots of toasted French bread. Again, regular bread is not keto-friendly as it is made with wheat flour, high in carbs.
So, as you can see, you can’t eat a classic onion soup recipe. But let me show you how French onion soup and keto can work together!
How to make keto French onion soup?
There are a few necessary tweaks to make an onion soup keto-friendly. Let me show you how to select the ingredients to make a keto low-carb French onion soup.
White onion. Onions are naturally high in carbs so I am using less onion in my keto version of the French onion soup. Still, a good enough amount to bring texture and flavor. Don’t use red onions, they are higher in carbs and the soup would be very sweet.
Erythritol. It’s the swap to sugar and it is a 100% keto-friendly keto sweetener that can caramelize onion just as well. Without adding any carbs.
Beef bone broth. Also known as keto beef stock sometimes, it’s 100% keto-friendly so you are safe here. If you want to make a vegetarian French onion soup, swap beef bone broth for vegetable broth.
Xanthan gum. This is your thickening agent, it contains barely any carbs and replaces high-carb flour found in the traditional French recipe.
White wine. Not all white wines are keto-friendly, you must use dry white wine like Sauvignon blanc. I also reduced the amount in this recipe to keep the net carbs per serving under control while having the tangy wine flavor.
Bay leaves. The secret French herb to any good French onion soup and many French dishes.
Salt. Optional if your beef broth is already high in salt.
Preparing the soup broth
It is super easy to make an onion soup. First, heat the butter, add finely sliced white onion, and cook for 20-25 minutes until soft, brown, and fragrant.
Then, add erythritol and salt to caramelize the onion. Finally, deglaze the onions with dry white wine and beef broth.
How to make onion soup toppings keto?
The best part of French onion soup is these crunchy croutons and broiled bubbly cheese on top! You don’t want to miss this even on keto so let me share my tricks to making quick keto croutons to add on top of your soup.
A traditional French soup is actually not topped with small bread croutons but with a thin slice of French baguette.
As a French let me share the secret for this!
French eat baguette daily and the slice of baguette on top of the onion soup is most of the time a stale baguette that has hardened on the kitchen countertop.
Then, we slice thin pieces of hard baguette and toast it in a bread toaster or oven to get it very hard and crispy.
Finally, we spread fresh butter on the bread and rub a fresh garlic glove to flavor the bread.
This is then added on top of the onion soup along with French grated cheese: usually Emmental, gruyere, or swiss cheese, and broil in the oven.
Keto crouton recipe
Of course, you can’t eat regular French bread or croutons on a keto diet. But I have a few solutions for you to mimic crispy croutons into your soup.
Then, release the bread cylinder and slice into thin bread slices. The slices will be very soft so bring them into a bread toaster on high until crispy.
Then, spread butter on the toasted bread slices and rub fresh garlic on the bread – onions and garlic are delicious, don’t skip!
Finally, top your keto onion soup bowl with a slice of this keto crouton recipe, add cheese and broil!
Et voila! you made a keto French onion soup. Now if someone asks you can you eat French onion soup on a keto diet, you can proudly answer YES, and serve this yummy recipe!
Using store-bought crouton alternatives
If you don’t feel like baking, use some of the options below to mimic croutons into your keto soup:
Pork rinds: that’s the closest alternative to croutons and it contains zero carbs so it’s a great addition to your keto meal.
Toasted seeds: like sunflower or pumpkin seeds.
How to store onion soup?
Onion soup stores very well in the fridge for up to 5 days, in a sealed container.
You can rewarm the soup in a saucepan or microwave. Then, broil in the oven with shredded cheese
How much can I eat?
This recipe serves 8 bowls. Serving size is 1 cup of soup and 1 slice of keto crouton and cheese. The entire low-carb onion soup bowl, including bread slices, contains 7.8 grams of net carbs or 6.1 grams of net carbs without the keto bread.
More keto soup recipes
Below I listed more keto soup recipes for you to try
Cook your keto bread in the microwave following the recipe HERE. Release the bread cylinder from the mug, cool 1 minute to steam out (this also avoid burning yourself), then cut into 4 even slices. You can repeat this bread recipe again to make 4 more croutons if you intend to serve 8 soup bowls at the same time.
Bring each bread slice into a bread toaster on high and toast until crispy on both sides. Set aside on a plate to cool.
Preheat oven to 350°F (180°C). When the oven is hot, turn to broil mode.
Remove bay leaves from the soup and discard.
Serve the soup
Ladle soup into 8 oven-proof soup bowls – 1 cup is 1 serving.
Brush butter on top of each slice of toasted keto bread. Rub fresh garlic glove on the bread slices to flavor bread.
Place 1 toasted bread slice on top of each bowl.
Cover the top of each soup bowl with 1/3 cup of grated French gruyere.
Broil in oven until the cheese is brown.
Store leftover soup in an airtight sealed container in the fridge for 3-4 days
Net carb in the nutrition panel below doesn’t include the slice of 90 seconds bread recipe on top of the soup. Add 1.6 grams of net carbs per slice, if bread cut into 4 slices or 1 gram if you cut the bread into 6 slices. Follow my bread recipe here and bake it in a tall coffee mug to create keto crouton that looks like French baguette slices.