Caramelized Leek and Roasted Butternut Squash Soup

Meet your new cold-weather MVP: a silky smooth, savory soup that feels restaurant-level but uses simple pantry staples. This butternut squash leek soup belongs on your holiday meal plan and your easy Sunday night stove-top rotation. Deeply caramelized leeks + roasted butternut = cozy, golden brown flavor with a naturally creamy texture—no heavy cream required. Finish with a drizzle of cashew cream and a quick herb pesto for a lovely crunch and next-level brightness.

Craving soup season? Try my oil-free, meal-prep-friendly Hearty Vegan Minestrone Soup, protein-packed Double Lentil Soup, or the light and brothy Easy Creamy Miso Ramen Bowls.

Why You’ll Love This Soup

• Ultra-creamy (dairy-free): Roasted squash and Yukon gold potatoes blend into a creamy butternut squash soup with a silky smooth finish.

• Flavor-first: Caramelized leeks bring a mild onion flavor and some sweetness from their natural sugars. Fresh herbs + lemon (or apple cider vinegar) keep every spoonful bright.

• Meal prep friendly: Cools and stores like a dream in an airtight container or mason jar—perfect for soup season and busy winter days.

• Flexible: Make it nut-free, add spice, or use pre-cubed butternut squash to cut prep time.

• Beginner-friendly: Use an immersion blender right in your large pot for a perfectly pureed soup, or a high-speed blender if you have one.

Key Ingredients & Easy Substitutions

• Butternut squash: One large butternut (~3 lb), peeled and cut into 1-inch cubes, or 1 (20-oz) container pre-cubed butternut to save time. Roasting at high heat develops golden edges and concentrated sweetness.

• Leeks: Use the white part and light green parts only; they’re tender with a mild onion flavor. Clean leeks well (directions below) to avoid grit!

• Yukon golds: Adds body for that creamy texture without dairy. Swap in sweet potato for a slightly sweeter vibe. 

• Garlic: Builds baseline savoriness in the leek mixture.

• Herbs: Rosemary + sage are classic; add fresh thyme or thyme sprigs for extra aroma. A bay leaf can go in during the simmer and be removed before blending too.

• Vegetable broth/stock: Choose low-sodium vegetable broth or vegetable stock to control salt. 

• Cashews: Most butternut squash soup recipes rely on heavy cream or sour cream for its silky texture, but this is a vegan soup, so we are using cashews instead. 

  • Looking for a nut-free option? Omit the cashews! For a creamy texture, stir in 1/2 cup full-fat coconut milk after blending, and add a drizzle of coconut milk on top before serving.

• Acid to finish: Lemon juice or apple cider vinegar (hello, vitamin C) balances the natural sugars in the roasted squash.

• For the pesto: Basil/parsley/cilantro/sage + pumpkin seeds/pepita seeds for a nut-free, dairy-free topper with a lovely crunch.

How to Clean Leeks (No Grit!)

1. Slice the leeks (white + light green parts).

2. Submerge in a big bowl of cold water; swish a couple of times to release sand.

3. Lift leeks out (don’t pour) so grit stays behind. Spin dry in a salad spinner or blot with a kitchen towel.

Step-by-Step Instructions

1) Roast the Squash (High Heat = Golden Brown)

• Heat oven to 425°F.

• Toss squash with a little olive oil, salt, and black pepper on a lined baking sheet.

• Roast 25–30 minutes, stirring once, until edges are golden brown and tender.

2) Caramelize the Leeks (Medium → Medium-Low Heat)

• Warm 2 Tbsp olive oil in your large pot over medium heat.

• Add leeks + ½ tsp salt; cook 12–18 minutes, lowering to medium-low heat as needed, until soft, sweet, and deeply golden (not burnt).

• Stir in garlic for the last 1–2 minutes.

3) Simmer

• Add cashews. roasted squash, diced Yukon gold, herbs (rosemary, sage; thyme + bay leaf optional), and vegetable broth.

• Bring to a gentle simmer on the stove top, cover, and cook 12–15 minutes until the potatoes and cashews are soft.

4) Blend to Silky Smooth

• Immersion blender: Purée directly in the pot to your desired consistency.

• High-speed/regular blender: Blend carefully in batches; vent the lid slightly and cover with a towel.

• Taste and finish with more salt, black pepper, and a squeeze of lemon or apple cider vinegar.

Toppings (Choose One—or All!)

• Cashew cream swirl: Blend soaked cashews with water + a pinch of salt until pourable. Want a “drizzle of cream” look? Drizzle in a spoonful of cashew cream at the end and then swirl with a toothpick.

•  Coconut milk (nut-free): Drizzle coconut milk on top of each bowl.

• Quick herb pesto: Pulse basil/parsley/cilantro/sage, pumpkin seeds, garlic, olive oil, lemon, and salt into a spoonable pesto.

• Heat lovers: Add red pepper flakes or a pinch of cayenne pepper.

• Crunch: Extra toasted pepita seeds on top = chef’s kiss.

Flavor Variations

• Curry Butternut: Stir 1–2 tsp curry powder into the leek mixture before adding broth.

• Sweet Potato Half-and-Half: Swap half the butternut for sweet potato for deeper color and sweetness.

• Thyme & Bay: Simmer with thyme sprigs + bay leaf for classic herbiness.

• Touch of Sweet: If your squash is bland, 1–2 tsp brown sugar balances acidity.

Pro Tips for the Best Texture

• Roast first. It’s the best way to amplify flavor without extra steps.

• Cut even 1-inch cubes so everything cooks at the same rate.

• Blend thoroughly. Let the blender run long enough for a truly silky smooth soup.

• Thin as needed. Add warm broth (or a splash of water) while blending to adjust to your desired consistency.

• Finish with acid. Lemon or ACV makes the flavors pop.

Meal Prep, Storage & Reheating

• Fridge: Cool completely, then store in an airtight container for 4 days.

• Freeze: Up to 3 months. Leave off the pesto and cream; add after reheating.

• Reheat: Warm gently on the stove over medium heat, adding a splash of broth or water to loosen.

• Pack it: Portion into mason jars for grab-and-go lunches. Press plastic wrap onto the surface of pesto before refrigerating to keep it vibrant.

FAQs

Can I use chicken broth or chicken stock?
For a truly vegan soup, stick to vegetable broth or vegetable stock. Using chicken broth/stock makes it non-vegan and changes the clean, herby profile.

Do I need a high-speed blender?
No. An immersion blender is the easiest (and mess-free) way. A regular blender also works—blend in batches.

Can I make it nut-free?
Yes. Skip the cashews and add an extra ½ Yukon gold for body. Use coconut milk for the swirl.

How can I make it spicier?
Blend in a pinch of red pepper flakes or cayenne pepper. Start small!

Can I skip roasting?
You can simmer raw squash, but roasting is the best way to build depth and that toasty, golden brown flavor.

What to Serve With Butternut Leek Soup

• Garlic-rubbed sourdough or crusty bread

• Simple arugula salad with lemon + olive oil

• Roasted veggies (sheet-pan Brussels or carrots) for an easy main dish combo

butternut squash leek soup, vegan soup, creamy butternut squash soup, immersion blender, vegetable broth, pureed soup, meal prep, pumpkin seeds, holiday meal, soup season, large dutch oven, baking sheet, coconut milk

Soup

American

Yield: 4

Author: Corey Taylor

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Caramelized Leek and Roasted Butternut Squash Soup

Silky butternut squash leek soup with caramelized leeks and roasted squash - no dairy needed. Made easy with fall supermarket staples like pre-cut butternut squash and veggie broth, it's a quick weeknight meal, great for meal prep, and easily dressed up with bright herb pesto and an optional cashew cream swirl for holiday tables.

Prep time: 15 MinCook time: 40 MinTotal time: 55 Min

Cook modePrevent screen from turning off

Ingredients

For the Soup

• 1 medium butternut squash (about 3 lb), peeled, seeded, cut into 1-inch cubes, or 1 (20-oz) container pre-peeled, pre-cubed butternut (about 4 cups)
• 3 tablespoons olive oil, divided (2 tbsp for pot, 1 tbsp for roasting)
• 1 large leek (or 2 small), white and light green parts only, halved, rinsed, thinly sliced (about 3 cups)
• 1/2 teaspoon fine sea salt, plus more to taste
• 2 cloves garlic, minced
• 1 medium Yukon gold potato, peeled and diced (about 1 heaping cup)
• 1/4 cup raw cashews
• 4 cups low-sodium vegetable broth (plus more to thin)
• 1 teaspoon chopped fresh rosemary (or 1/2 teaspoon dried)
• 4 fresh sage leaves, chopped (or 1/2 teaspoon dried)
• Optional: 1 bay leaf
• Freshly ground black pepper, to taste
• 1–2 teaspoons fresh lemon juice or apple cider vinegar, to finish

For the Cashew Swirl

• 1/4 cup raw cashews, soaked (hot water 10 minutes) and drained
• 1/4–1/3 cup water (to desired consistency)
• Pinch of salt

For the Quick Herb Pesto (Dairy-Free)

• 1 packed cup fresh herbs (basil, parsley, or cilantro, or a combo)
• 1/4 cup toasted pumpkin seeds (pepitas) or walnuts/almonds
• 1 small clove garlic, chopped
• 3–4 tablespoons olive oil
• 1–2 teaspoons lemon juice
• 1/4 teaspoon salt

Instructions

1. Roast the squash. Preheat oven to 425°F. On a parchment-lined baking sheet, toss squash with 1 tablespoon olive oil, a pinch of salt, and pepper. Roast 25–30 minutes, stirring once, until tender with caramelized, golden edges.
2. Caramelize the leeks. Meanwhile, heat 2 tablespoons olive oil in a large Dutch oven over medium heat. Add leeks and 1/2 teaspoon salt; cook 12–18 minutes, stirring often and lowering to medium-low as needed, until very soft and deep golden (not burnt). Stir in garlic for the last 1–2 minutes.
3. Simmer. Add cashews roasted squash, diced potato, rosemary, sage, and optional bay leaf. Pour in 4 cups vegetable broth. Bring to a gentle simmer, cover, and cook 12–15 minutes until the potato is very tender and the cashews are soft.
4. Blend until silky. Remove bay leaf if used. Blend with an immersion blender right in the pot until completely smooth, or add to a blender, blending in batches. Thin with a splash of warm broth or water to your desired consistency. Season to taste with more salt and black pepper, then finish with 1–2 teaspoons lemon juice or apple cider vinegar.
5. Make the cashew cream (optional). In a small blender, blend cashews with 1/4–1/3 cup water and a pinch of salt until silky and pourable. For nut-free, blend pepitas or sunflower seeds with 1/3 cup water and a pinch of salt until smooth; add water as needed.
6. Make the quick herb pesto (optional). Pulse herbs, pumpkin seeds, garlic, olive oil, lemon juice, and salt to a spoonable pesto.
7. Serve. Ladle soup into bowls. Swirl with cashew cream (or seed cream) and add a spoonful of herb pesto.

Notes

• Nut-Free Option: Omit the cashews. For a creamy texture, stir in 1/2 cup full-fat coconut milk after blending, and add a drizzle of coconut milk on top before serving.

• Make-Ahead/Meal Prep: Soup thickens as it cools, so whisk in a splash of vegetable broth when reheating. Store in airtight containers (mason and weck jars work!) up to 4 days in the fridge, or up to 3 months in the freezer.

Nutrition Facts

Calories

452

Fat

30 g

Sat. Fat

5 g

Carbs

43 g

Fiber

7 g

Net carbs

35 g

Sugar

8 g

Protein

9 g

Sodium

472 mg

Cholesterol

0 mg

Please note: I am not a certified dietitian or nutritionist. Nutrition info is calculated automatically and is for informational purposes only.

https://www.thevegansix.com/recipes/butternut-squash-leek-soup

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