Keto French Onion Soup is a low-carb take on the typically carb-loaded French onion soup version and you won’t be feeling like you’re compromising on taste either, you’ll be getting that full taste of caramelised onions, beef broth and ooey gooey cheese topping, without the guilt. Though traditional recipes typically use bread or flour to add thickness, this keto-diet variety avoids the added starch and provides a meal as deliciously comfortable and filling as ever. The onions are slowly cooked to a golden sweetness, and then simmered in a rich, herb-scented beef broth. It’s indulgent with a sprinkle of melted Gruyère or mozzarella cheese, but it won’t blow your keto diet.
Cuddle up on the sofa, host a dinner party, or even as the first thing a special supper, keto french onion soup is hearty and fancy at the same time! It’s not only low carb, but it’s a bowl of warm, nutrient-rich goodness. By replacing high-carb ingredients with clever keto substitutes, the flavour is there, but not at the expense of your diet. Dish up with some keto bread or a crunchy salad and you’ve got a full meal! Whether you’re new to keto cooking or a veteran pro, this is one of those soups that will have you going back for more again and again!

Keto French Onion Soup Recipe
Now let’s get into this tasty Keto French Onion Soup Recipe. Here will will talk about all the necessary ingredients, pots, cookware, preparation steps, time, calories, and everything you need to know in order to make this one at your home successfully. Once you follow this recipe, you’ll discover what goes into the perfect low-carb take on a French classic that’s comforting and good for you.

Keto French Onion Soup
Ingredients
Equipment
Method
- Caramelize the Onions: Add the butter and the olive oil to a large pot over medium heat. Add sliced onions and cook slowly, tossing them often, until the onions are soft, golden-brown and caramelized (about 25 – 30 minutes).
- Season: Fold in garlic, thyme, salt, and pepper. Fry for 2 minutes until fragrant.
- Simmer Broth: Pour in beef broth and chicken broth, then add bay leaves, and let the soup to simmer for 20 minutes, to infuse all the flavors.
- Prepare Bowls: Ladle the hot soup into oven-safe bowls, then place a slice of keto bread (optional) on top.
- Add Cheese: Sprinkle generously with shredded Gruyère or mozzarella cheese.
- Broil and Serve: Put under a broiler until cheese is melted and bubbly. Let stand 5 minutes before serving hot.
Notes
- Use a combination of beef and chicken broth for depth of flavour.
- Caramelising onions requires patience, for sure — low and slow yields the sweetest, most flavourful results.
- Sprinkle in a little dry white wine (if you have any) for authentic flavour.
- Opt for Gruyère cheese for the most classic taste.
- Only bake it in oven-safe bowls, and broil it for the cheesy crust.
Keto French Onion Soup Nutrition
Nutrient | Amount (per serving) |
Calories | 310 kcal |
Carbohydrates | 9g |
Net Carbs | 6g |
Protein | 14g |
Fat | 24g |
Saturated Fat | 12g |
Fiber | 3g |
Sugar | 4g (from onions) |
Cholesterol | 55mg |
Sodium | 720mg |
Potassium | 350mg |
Calcium | 220mg |
Vitamin A | 18% DV |
Vitamin C | 9% DV |
Iron | 6% DV |
Frequently Asked Questions
Ques: Can I make Keto French Onion Soup ahead of time?
Ans: Yes, it stores well in the fridge for 3–4 days.
Ques: Do I need keto bread for this soup?
Ans: No, it’s optional—you can just use cheese.
Ques: Can I freeze this soup?
Ans: Yes, but add cheese only when reheating.
Ques: Which cheese works best?
Ans: Gruyère is classic, but mozzarella or provolone works too.
Ques: Is this soup gluten-free?
Ans: Yes, as long as you skip regular bread.

Hi, I’m Ereka Vetrini, the editor and voice behind KetoRecipesMom.com – a space dedicated to helping busy moms and families embrace the keto lifestyle with ease, confidence, and delicious food!
As a mom, home cook, and health-conscious foodie, I understand the daily challenge of preparing meals that are both nutritious and kid-approved. That’s why I started this blog—to share simple, family-friendly keto recipes that save time in the kitchen and make healthy eating truly enjoyable.