This Low Carb French Onion Soup is made with thinly sliced caramelized onions, a rich broth with wine and brandy and topped with a crispy low carb french baguette and a gooey gruyere cheese.
This warm and cozy keto french onion soup recipe will feel like you are having a traditional french onion soup.
When fall is upon us I start to crave soups. One of my favorite soups is french onion soup. I was always attracted to the golden layer of bubbly cheese on top and this onion soup keto version will not disappoint.
However, as I make this soup and add each ingredient I learn to understand the complexity of the flavors of this delicious french onion soup. I now thoroughly enjoy the flavourful notes of the broth and onions more than the crusty cheese.
- 🥘 Ingredients for low carb french onion soup
- Other low carb soup recipes you might enjoy
- 👨🏻🍳 Steps to make this onion soup
- 👨🏻🍳 Substitutions and Variations
- ♨️ Top tips and serving suggestions
- 🥣 Equipment used to make this french onion soup
- 💭 Frequently asked questions
- 🍽 Other low carb recipes you may enjoy
- Low Carb French Onion Soup
🥘 Ingredients for low carb french onion soup
This keto french onion soup is made with traditional french onion soup ingredients. However, some purists might not agree with using red wine instead of white but I prefer the bolder and more complex flavors of red.
This low carb french onion soup is also topped with a couple of slices of crusty low carb french baguette that I made specifically for this recipe. I then add some shredded gruyere cheese and broil it in the oven to give it that nice bubbly gooey crust on top.
- Caramelized Onions: this soup will be nothing without these savory and sweet onions
- Beef Broth: giving this soup a salty and savory beef flavour
- Red Wine: the rich and bold complexity of red wine gives this soup extra flare and je ne sais quoi 😘
- Brandy: adding notes of flowers, fruit and citrus to this low carb french onion soup
- Crusty Baguette: as mentioned earlier I developed a Low Carb French Baguette recipe specifically for this soup. This soup can also be enjoyed without the bread.
- Gruyere Cheese: this cheese is in my top 3 of all cheeses. Alternatively, you can use an Emmental but I prefer the nutty flavors of gruyere cheese.
👨🏻🍳 Steps to make this onion soup
How to make low carb French onion soup?
STEP 1: add the butter and oil over medium heat in a dutch oven or heavy bottom pot, then add the thinly sliced onions with a dash of salt. Cook on medium heat until softened, stirring often. Once softened reduce heat to medium low and continue to cook for 30 to 40 minutes. Stirring often during this whole process.
STEP 2: Once the onions have become slightly browned add the garlic and allow to soften for 2 minutes. Next, add the red wine and brandy and continue to simmer on low until the wine is reduced to half.
STEP 3: add the beef broth, salt and pepper. Bring to a boil, then cover and simmer for 1 hour. While it's simmering slice the baguette into ½ inch slices and brush both sides with olive oil. Place on a baking sheet and bake in the oven at 400°F for 3-5 minutes, flipping halfway through. Once out of the oven, rub each baguette with a half clove of garlic.
- STEP 4: add the soup to an oven soup bowl like a ramekin or french onion soup bowl. Top with two slices of the low carb bread and then top with shredded gruyere cheese.
STEP 5: Place bowls on a baking sheet and broil in the oven for about 4 minutes just to get the cheese topping nice and bubbly. Serve with a sprig of thyme on top (optional)
👨🏻🍳 Substitutions and Variations
There are many variations to the classic French onion soup. Here are some other ways you can make this low carb soup.
- Cheese - use any cheese that melts well such as Emmental, provolone, fontina or mozzarella
- Bread - as an alternative use any low carb bread you can purchase in grocery stores, cut into the size of your bowl and toast in the oven just the same
- Red Wine: if you prefer white wine you can use the same amount instead of red
See my other Keto Soup Recipes
♨️ Top tips and serving suggestions
Top Tip: If you don't have oven safe bowl you can place the cheese on top of the baguette slices while on the baking sheet and melt them in the oven. Then just simply top the soup with the crusty and cheesy baguette slices.
- Serving: enjoy in an oven-safe bowl topped with crispy baguette and bubbly cheese. Either as a side or it can be a whole meal in itself.
- Storage: if you have leftovers or want to make this soup ahead you can store the broth in an airtight container in the fridge for up to 5 days. When ready to eat, serve in oven safe bowls and top with the crispy bread and cheese, broil in the oven until soup is warm and cheese is bubbly on top.
🥣 Equipment used to make this french onion soup
I find having this low-carb french onion soup recipe in traditional oven safe bowls truly give you that classic french soup feeling.
Another option would be to use oven-safe ramekins or souffle bowls as long as they are at least 10 oz in size.
A medium sized dutch oven pot always comes in handy for soups and stews.
Baking sheets are a must for this recipe in order to make the crusty bread and to place the oven safe bowls onto in case they boil oven and not make a mess in the oven.
💭 Frequently asked questions
Traditional French onion soup is made with beef broth, and caramelized onions and topped with croutons or a large piece of bread and cheese melted on top.
Yellow onions tend to caramelize best but a white onion will also work. I suggest not using red onions and they will be too sweet for this recipe.
Any cheese that will melt nicely in the oven like provolone, fontina, Emmental or mozzarella.
No, just replace the alcohol liquids with the same amount of beef bone broth.
A cup of this soup with the bread and cheese has roughly 9g of net carbs. Therefore, depending on your daily macros this soup may or may not fit into a keto diet.
You can reduce the carbs by using fewer onions. Although this recipe is considered sugar-free, onions will release some sugar while sauteing them. Reducing the onions to only one will still give you that onion flavor and be enjoyable. You may also want to omit the keto bread to limit the number of carbs.
I used a very dry low carb red wine for this soup.
🍽 Other low carb recipes you may enjoy
Low Carb French Onion Soup
- 2 tablespoon butter
- 2 tablespoon olive oil
- 3 medium onions thinly sliced
- 2 cloves garlic minced
- ¼ cup dry red wine
- 1 tablespoon brandy
- 32 oz beef broth 1 carton (900ml)
- ¼ teaspoon salt
- ¼ teaspoon black pepper
Crispy Baguette Slices
- 4 slices low carb french baguette see recipe
- ½ clove garlic
- 1 tablespoon olive oil
- ¼ cup gruyere cheese shredded
- Add the butter and oil to a medium sized dutch oven or heavy bottom pot. Allow butter to melt and then add the thinly sliced onions with a dash of salt.2 tablespoon butter, 2 tablespoon olive oil, 3 medium onions
- Cook on medium heat until softened, stirring often. Once softened reduce heat to medium low and continue to cook for 30 to 40 minutes. Stirring often during this whole process.
- Once the onions have become slightly browned add the garlic and allow to soften for 2 minutes. Next add the red wine and brandy and continue to simmer on low until wine is reduced to half.2 cloves garlic, ¼ cup dry red wine, 1 tablespoon brandy
- Add the beef broth, salt and pepper. Bring to a boil, then cover and simmer for 1 hour.32 oz beef broth, ¼ teaspoon black pepper, ¼ teaspoon salt
- After the hour, add the soup to an oven soup bowl like a ramekin or french onion soup bowl. Top with two slices of the baguette and then top with shredded gruyere cheese.4 slices low carb french baguette, ¼ cup gruyere cheese
- Place bowls on a baking sheet and broil in the oven for about 4 minutes just to get the cheese topping nice and bubbly. Serve with a sprig of thyme on top (optional)
Crispy Baguette Slices
- Slice baguette into ½ inch slices and brush both sides with olive oil. Place on baking sheet and bake in the oven at 400°F for 3-5 minutes, flipping halfway through. Once out of the oven rub each baguette with a half clove of garlic.½ clove garlic, 1 tablespoon olive oil
This recipe card provides the basic details to make this recipe. For more information, questions or variations please review the content above the recipe card.
Updates and Revisions
If conflicting information between the video and recipe card, the recipe card will always have the most up to date information, ingredients and instructions.
All nutritional information is based on third-party calculations and should be considered estimates. Actual nutritional content will vary with brands used, measuring methods, portion sizes and more.
🌡️ Food safety
- Cook to a minimum temperature of 165 °F (74 °C)
- Do not use the same utensils on cooked food, that previously touched raw meat
- Wash hands after touching raw meat
- Don't leave food sitting out at room temperature for extended periods
- Never leave cooking food unattended
- Use oils with high smoking point to avoid harmful compounds
- Always have good ventilation when using a gas stove
See more food guidelines
Everyone at my house loved how satisfying this!
Amy Liu Dong
I am thinking of a soup recipe to make today, and this one is perfect!
It looks delicious and easy!
Great, hope you enjoy it.
We loved this French Onion Soup! A great recipe for this time of the year!
Thank you Lexa.
Another winning recipe Oscar! Love the low carb bread…. Brilliant!
Mmmm, this soup was so full of flavor! Better than any restaurant french onion soup. It is going on the dinner rotation schedule! Thanks!
Right on. Thanks Jeri.
This soup was delicious! Perfect for a cold Fall evening.
Perfect soup for a cold evening. Thanks Amanda.
I love french onion soup. I will give your recipe a try. Looks amazing and so delicious!
It's been ages since I had French Onion Soup and your recipe is simple to make.
So happy to have stumbled across this recipe. I have been craving anything French onion something fierce lately. Next week I start back up on a low-carb diet so this will definitely be on the menu. I'm thrilled that you have a recipe for low-carb baguette as well because you just can't have French onion soup without the bread
I agree, you need the bread in the soup 🙂
French onion soup is my favorite and I loved the way you reduced the carb amount! This was delicious!
Thanks so much Kayla.
Yaas! this looks amazing! I cannot wait to give it a try. Thanks for sharing.
Delicious and full of flavour, this soup will be a fantastic starter for our festive menu also!
This soup is so hearty and flavorful!
Your French onion soup was a big hit with my family, I'll definitely be making it again!
One of my favorite soups to make for my husband. Thanks for sharing this delicious soup.
Welcome, enjoy 🙂