Name: Keto Butternut Squash Soup
Prep time: 5 min
Cook time: 15 min
Total time: 20 min
Ingredients: 3 tbsp butter (ghee or olive oil); 2 medium celery stalks (80g / 2.8oz); 8.8 oz / 250g butternut squash (peeled + chopped into 1 cm cubes); 10.6 oz / 300g cauliflower florets (chopped into 1 cm cubes); 2 garlic cloves (minced); 1 tsp onion powder; 1.5 tbsp fresh thyme leaves (1.5g or 1 tbsp dried thyme); 1 tbsp fresh rosemary (chopped (1.5g) or 3/4 tbsp dried rosemary); salt and pepper to taste; 5.3 cup / 1.25l chicken stock (2.6 pint); 1 tbsp olive oil

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This creamy low carb butternut squash soup is such a comforting and quick meal! It's a family favourite for autumn and winter and ready in just 25 minutes. Find out which ingredient I'm adding to my easy keto butternut squash soup to keep the carbs down.

butternut squash and cauliflower soup in a bowl

Why This Recipe Works

Perfect for cozy fall and winter dinners
Rich and velvety texture
Awesome butternut squash flavor
Cauliflower keeps the carbs down without losing creaminess. It's the invisible keto helper!
Ready in 25 minutes
Great for meal prep and freezing

I am a huge fan of low carb soup recipes and I have a bunch of them on my website already - from simple healthy vegetable soups such as this Creamy Broccoli Pistachio Soup to decadent keto soups like my Bacon Cheeseburger Soup Recipe.

There's nothing like a warming, cozy soup when it's cold outside!

Now, let's get straight to it. I love making recipes with pumpkin when it is in season during autumn and winter. But there's only one type of pumpkin that's available all year round here in the UK - and is always reasonably priced: butternut squash.

And here is where it gets tricky. Butternut squash is a starchy vegetable. This means it is high in carbs and it is generally not considered to be suitable on a low carb diet and especially on a keto diet plan.

Jump to:

Why This Recipe Works
How Butternut Squash Soup Can Be Keto
Ingredients
Instructions
How to serve
Variations
How to thicken low carb butternut squash soup
Storage
Related Recipes
Recipe

How Butternut Squash Soup Can Be Keto

100 grams of butternut squash contain 9.7 grams of net carbs. Compared to other vegetables, this is high.

So, is the solution to simply use a tiny amount of butternut and have a watery soup? Of course not.

To ensure we're making a low carb butternut squash soup recipe, the remaining ingredients must considered carefully to keep the carb count in check.

And guess what my secret ingredient for this soup recipe is? Cauliflower!

By adding cauliflower to the soup, you're making it super creamy and thick. And you're still getting that lovely butternut squash taste - without having to use a large amount of butternut.

Of course, at 9.5g net carbs per serving this recipe is still higher in carbs than all my other soup recipes on Sugar Free Londoner. In fact, I'm pretty certain some people are going to complain about me calling it a keto butternut squash soup.

Please save your breath. If you're mindful about what you're eating the rest of the day, you can definitely incorporate this soup into a keto diet.

Also try my keto pumpkin soup!

Ingredients

Here you can see all ingredients I'm using for my keto friendly butternut squash soup:

Butternut Squash - Choose a small, firm butternut squash. Cubed frozen squash is a great shortcut if you are short on time.
Celery - A must in any soup and very low carb.
Cauliflower - Adds body and a silky-smooth texture. Its mild flavor blends into the soup. You can't taste it at all.
Herbs and spices: garlic, onion powder, thyme, rosemary, salt and pepper. 1 teaspoon of onion powder is much lower in carbs than a real onion!
Chicken stock - I always use it in my vegetable soups for a fuller flavor. Vegetable stock also works.
Butter (or use olive oil for dairy free), for frying

Instructions

This section contains step-by-step instructions and photos that show how to make this recipe. See the recipe card for full information on ingredients and quantities

butternut squash, cauliflower, celery and spices in a saucepan

Step 1: Heat butter in a large saucepan. Once hot, add the celery, butternut squash, cauliflower, garlic, onion powder, thyme, rosemary, salt and pepper and fry on a medium heat.

Step 2: Add the chicken broth (I like to make my own chicken bone broth from leftover chicken bones) and simmer until the butternut squash is soft.

Step 3: Transfer to a blender and blitz in a food processor or with an immersion blender until smooth. Taste and adjust seasoning to your liking.

Katrin's Top Tips

Fresh versus frozen butternut squash: Fresh has a slightly creamier texture, but frozen is the "busy mom" alternative. You can use it straight from frozen and simply simmer the soup for a few extra minutes.

Immersion blender versus countertop blender: A countertop high speed blender will make the creamiest soup and I recommend it. However, an immersion blender is quick because you blend directly in the pot (and there's less washing up). Immerse it properly or you might splash yourself with hot soup!

How to serve

Top the soup with olive oil and optional cracked black pepper, fresh thyme and a swirl of cream (dairy heavy cream or coconut milk or even sour cream, whichever you prefer).

Variations

Here are a few ideas how you can change up this soup:

Roast the cauliflower and the butternut squash before adding to the soup. Roast the butternut for about 45 minutes on a parchment lined baking sheet at 200F and the cauliflower florets for about 25 minutes. This will intensify their taste.

Add coconut milk into the soup. For an even creamier result, replace ¼ cup or 60ml of the chicken stock with unsweetened coconut milk or even coconut cream from a can.

Change up the spices: Use ginger, cinnamon and nutmeg instead of the rosemary and thyme for a warm, mellow variation.

Make it vegetarian: Use vegetable stock instead of chicken broth.

How to thicken low carb butternut squash soup

Cauliflower is my favourite way of adding thickness to this soup. In my opinion, it's the best compromise in terms of taste AND net carbs.

Here are some other ways you can thicken this butternut soup:

Use more butternut squash. This is the most obvious way and tastes great. If you're making a Whole 30 paleo butternut squash soup or you're not bothered about adding more carbs, it's a great solution.
Use almonds. Add ¼ cup or 40 grams of blanched almonds to the soup. The nuts become nice and soft during cooking and can be pureed alongside the soup.
Use xanthan gum, ground chia seeds or gelatine. Not my favourite method in terms of texture, but a possibility. Try ½ teaspoon of xanthan gum and 1 -2 teaspoon of ground chia seeds or gelatine.