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keto butternut squash soup with crispy fried sage drizzled with olive oil, fresh thyme, and heavy cream
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5 from 2 votes

Keto Butternut Squash Soup

This Low Carb Butternut Squash Soup Recipe is truly delightful. Roasted butternut squash and cauliflower in a creamy broth packed with fresh herbs, onion and garlic. This rich, comforting soup is full of flavor, with less carbs so it’s the perfect lunch side on the keto diet.
Prep Time20 minutes
Cook Time45 minutes
Total Time1 hour 5 minutes
Course: Soup
Cuisine: American
Servings: 12 servings
Calories: 133kcal
Author: Briana


  • 1 medium butternut squash, halved lengthwise, seeds removed
  • 1 head cauliflower, cut into pieces
  • 3 tablespoons olive oil
  • 1 tablespoon kosher salt, divided
  • 1.5 teaspoons black pepper
  • 3 tablepsoons unsalted butter
  • 1 medium yellow onion, diced
  • 6 cloves garlic, minced
  • 2 tablespoons fresh sage, minced
  • 2 tablespoons fresh thyme leaves
  • 1 teaspoon smoked paprika
  • ½ teaspoon red pepper flakes
  • ½ teaspoon ground nutmeg
  • 4 cups chicken broth
  • 1 cup heavy whipping cream


  • Preheat the oven to 400°F. Prepare two large baking sheets with parchment paper. Add cauliflower and butternut squash to the baking sheets, and coat with olive oil, then season generously with salt and pepper. Roast until golden brown and fork tender, about 35-45 minutes, tossing halfway through.
  • Meanwhile, in a large stock pot or dutch oven, melt the butter over medium heat. Add in onion, with a pinch of salt and cook until softened and translucent, about 5-7 minutes. Once softened, add in fresh herbs, spices and garlic, and cook until garlic is fragrant, about 30 seconds.
  • Add in the roasted cauliflower and squash, then pour in stock and simmer for 10-15 minutes. After 15 minutes, stir in heavy cream to warm through. Adjust seasonings to taste.
  • Transfer soup mixture to a blender or use an immersion blender to puree the soup. Once smooth, ladle into bowls and garnish with sour cream or heavy cream, salt, pepper, and herbs. *For an extra special flavor, fry a few pieces of sage in some olive oil on the stovetop for garnishes.
  • Store in an airtight container in the fridge for up to 5 days. Gently simmer on the stovetop or reheat gently in the microwave to warm up.


  • Butternut squash is a naturally starchy vegetable, so the serving sizes are small. This soup is perfect as a side to any meal. 
  • Season to taste, and feel free to substitute fresh herbs with dried herbs, a good rule of thumb is to use about ⅓ of the amount of dried as you would use fresh. So in this case, use about 2 teaspoons of fresh thyme and 2 teaspoons of fresh sage in place of 2 tablespoons each of fresh. 
  • Smoked paprika and red pepper flakes are optional.
  • Garlic powder and onion powder can be substituted for fresh onion and garlic. 
  • If you don't wish to roast the squash and cauliflower beforehand, you can always simmer them in the broth alongside the aromatics instead. Simmer until veggies are nice and soft, about 20-30 minutes, then puree as normal before serving. We do highly recommend roasting the veggies if you get the chance! It really deepens the flavor of this soup. 


Calories: 133kcal | Carbohydrates: 11g | Protein: 2g | Fat: 10g | Saturated Fat: 5g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 1g | Cholesterol: 24mg | Sodium: 767mg | Potassium: 412mg | Fiber: 2g | Sugar: 2g | Vitamin A: 6092IU | Vitamin C: 38mg | Calcium: 66mg | Iron: 1mg