This sweet and creamy butternut squash and leek soup embodies all the Fall vibes. It takes a little more time to caramelize the vegetables, but the rich depth that this step adds will take your soup to the next level. And since we're making it from scratch, I'll tell you how to select the best squash and leeks for the best flavor and easier preparation.
Butternut squash leek soup is perfect for Fall, as the weather turns cooler. I find myself craving a hot bowl of creamy, nourishing soup during these shorter days. Plus its bright orange color breaks up the mundanity of the seemingly endless gray clouds here in the PNW this time of year. It’s like a big, warm hug in a bowl!
If you're looking for more delicious soup recipes for Fall, try vegan chickpea soup, roasted butternut squash and carrot soup, or vegetarian chili.
This butternut squash and leek soup is naturally gluten free and dairy free. Instead of heavy cream or sour cream, I like using coconut milk. Coconut milk adds a creamy texture that’s perfect in this soup. And the roasted squash and leeks have an insanely rich caramelized flavor that pretty well covers up the coconut flavor. So even if you aren't a fan of coconut, you'll hardly notice it's in the soup.
Ingredients and Substitutions
- Butternut squash - Has a naturally sweet flavor that is enhances when it's roasted. It also softens when baked to become creamy. You could substitute other squashes like acorn squash or pumpkin.
- Leeks - Similar to onions, but have a milder, sweeter flavor. When roasted, they soften and develop a buttery flavor. You could substitute one yellow or white onion, or shallots.
- Olive oil - Coats the leeks uniformly so they cook and caramelize evenly. It also prevents the leeks from drying out, so they can soften as they roast in the oven.
- Kosher salt - I recommend using kosher salt since it disperses quickly and has a better flavor than table salt. But if you only have table salt, cut the measurement of salt in half, since kosher salt grains are much bigger.
- Unsalted butter - Adds a savory, warm, buttery flavor. To keep this soup vegan, you can substitute vegan butter.
- Garlic - I recommend using freshly minced garlic cloves for the most potent flavor. Or you can substitute about a teaspoon of garlic powder.
- Dried thyme - Adds an earthy herb flavor that's quintessential to Fall. If you have fresh thyme instead, use one tablespoon of the leaves and make sure you remove any stems.
- Ground black pepper - Adds an essential kick of pepper flavor.
- Vegetable broth - Adds a savory flavor to balance the sweet squash, and adds liquid so the soup isn't too thick. You could substitute chicken broth or beef broth.
- Coconut milk - Thickens the soup and adds more creamy texture. You could substitute heavy cream.
How to Select a Good Butternut Squash
- Whole: While peeled and pre-cut squash is more convenient, a whole, uncut squash will last longer and they usually have a fresher flavor.
- Texture: Select a squash that is firm and heavy with smooth skin.
- Color: Butternut squash should be beige or tan. Don't get one with green patches, which probably means it isn't ripe.
- Stem: Don't select a squash with a moldy stem. Pick one with a firm, dry stem.
- Shape: The neck is usually thinner and longer than the more round bottom of the squash. The more uniformly it's shaped, the easier it will be to scoop out the flesh from the skin.
How to Make this Soup
Below are the general steps to make this butternut squash and leek soup. For the full step-by-step directions and ingredient measurements, scroll down to the recipe card at the bottom of this post.
1. Cut the butternut squash in half lengthwise (from the stem down to the bottom).
3. Slice the white parts and tender green parts of the leeks into roughly one-inch chunks.
5. Place the squash halves cut-side-down on a baking sheet lined with parchment paper and spread out the chopped leeks.
7. Melt the butter in a large pot or Dutch oven on medium-low heat.
9. After the squash has cooled a bit, scrape out the squash from the skin, and discard the skin. Add the roasted squash and leeks to the pot.
11. Blend the soup. If using an immersion blender, you can blend it while it's hot. If using a normal blender, allow the soup to cool first.
2. Scoop out the seeds and string stuff from inside of the squash and discard.
4. Toss the leeks in a small bowl with the olive oil and ¼ teaspoon of the salt.
6. Bake the butternut squash and leeks for about 40 to 50 minutes at 350 F, until both are easily pierced with a fork all the way through.
8. Add the minced garlic and cook for 2 to 3 minutes, until it smells really fragrant and the garlic has softened.
10. Add the thyme, black pepper, remaining salt, vegetable broth, and coconut milk. Bring to a boil, then simmer for 20 minutes.
12. To serve, ladle into bowls. Garnish with chives, roasted pumpkin seeds, more black pepper, a dollop of cream, croutons, or other herbs.
Recipe Tips
- Roasting the squash and leeks first takes extra time, but trust me, the depth of flavor that comes from caramelizing the vegetables is so worth it!
- To add a kick of heat, add a quarter teaspoon of cayenne pepper or a half teaspoon of smoked paprika.
- If you don’t have leeks, you can substitute shallots or sweet onions. I still recommend roasting them in the oven, but watch them closely, as they may cook faster than the squash. Alternatively, you could sauté them in olive oil or butter on the stove.
- Instead of thyme, you could use rosemary or sage.
- If you don’t like coconut milk, replace it with an extra cup of broth. Just note that your soup may not end up as creamy. You can also replace the coconut milk with heavy cream, if you don’t need your soup to be dairy free.
- If you blend hot soup in a blender, it’ll build up pressure and could cause the soup to explode! So let your soup cool a bit, and let it vent out the top, with a towel covering the top to catch any splatters.
Storing
Fridge: Allow leftover soup to cool completely. Store in the fridge in airtight containers for up to 4 days.
Freezer: Allow leftover soup to cool completely. Store in the freezer in airtight containers for up to 3 months.
Frequently Asked Questions
You can leave this soup plain, or garnish it with roasted pumpkin seeds, a dollop of cream or coconut milk, croutons, roasted chickpeas, or fresh herbs like thyme, rosemary, or sage.
Broth is usually made from simmering meat and/or vegetables for an hour or less, and it has a light flavor.
Stock is usually made from simmering bone and/or vegetables for at least several hours, and it has a rich flavor.
I recommend using broth in this recipe, for its lighter flavor and color.
Technically the skin is edible, but it's really tough and fibrous, and I don't think it's very pleasant to eat. Therefore, I recommend to remove and discard the skin after the squash has been roasted.
What to Serve with this Soup
- Crusty bread, toast, or cornbread
- Salad like a simple Caesar salad
- Roasted vegetables
- Rice or lentils
- Grilled cheese sandwiches
Butternut Squash and Leek Soup
Ingredients
- 4 pounds butternut squash (1 large squash)
- 2 leeks (about 1 pound)
- 2 tablespoon olive oil
- 1¼ teaspoon kosher salt, divided
- ¼ cup unsalted butter
- 3 cloves garlic, minced (about 1 tablespoon)
- 1 teaspoon dried thyme
- ½ teaspoon ground black pepper
- 3 cups vegetable broth
- 14 ounces coconut milk (1 can)
Instructions
Roast the Butternut Squash and Leeks
- Preheat the oven to 350 F. Line a baking sheet with parchment paper.
- Cut the butternut squash in half lengthwise (from the stem down to the bottom). Scoop out the seeds and discard. Place the halves cut-side-down on the baking sheet. Slice the white parts and tender green parts of the leeks into roughly one-inch chunks. Toss the leeks in a small bowl with the olive oil and ¼ teaspoon of the salt. Add the seasoned leeks to the baking sheet. (Discard the dark green parts of the leeks, or save them to make homemade vegetable stock.)
- Bake the butternut squash and leeks for about 40 to 50 minutes, until both are easily pierced with a fork all the way through.
- Let the squash cool for a few minutes, then scrape out the squash from the skin, and discard the skin.
Make the Soup
- Melt the butter in a large pot or Dutch oven on medium-low heat.
- Add the minced garlic and cook for 2 to 3 minutes, until it smells really fragrant and the garlic has softened.
- Add the baked squash and leeks along with the dried thyme, black pepper, remaining 1 teaspoon of salt, vegetable broth, and coconut milk. Bring to a boil on high heat, then reduce the heat to medium-low and simmer for 20 minutes.
- Either use an immersion blender to blend the soup right away. Or allow the soup to cool then work in batches to blend it in a high speed blender. If you blend hot soup in a blender, it’ll build up pressure and could cause the soup to explode! So either let your soup cool, or let it vent out the top, with a towel covering it to catch any splatters.
- To serve, ladle into bowls. Garnish with chives, roasted pumpkin seeds, more black pepper, a dollop of cream, croutons, or other herbs. Enjoy!!
Notes
- Roasting the squash and leeks first takes extra time, but trust me, the depth of flavor that comes from caramelizing the vegetables is so worth it!
- To add a kick of heat, add a quarter teaspoon of cayenne pepper or a half teaspoon of smoked paprika.
- If you don’t have leeks, you can substitute shallots or sweet onions. Watch them closely in the oven, as they may cook faster than the squash. Alternatively, you could sauté them in olive oil or butter on the stove.
- Instead of thyme, you could use rosemary or sage.
- If you don’t like coconut milk, replace it with an extra cup of broth. Note that your soup may not end up as creamy. You can also replace the coconut milk with heavy cream, if you don’t need your soup to be dairy free.
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