It’s a mouthful of a name, but this spiced squash & lentil soup with caramelized onion and fennel is about to become your winter staple.
Squash and lentil soup. The words strung together conjure up an image: brown, boring, and mushy. But so much flavor can be hidden in those beige hues. The squash is cooked down until it falls apart like a coarse mash. The fennel and onion are sautéed until deeply caramelized. The sweet and the savory counter each other, enhanced and balanced by a slash of acid in the end.
Once all the chopping is done, most of the work is done for you by the powers of heat, time, and patience. The caramelization of the fennel and onion cannot be rushed, neither the breaking down of the squash. But the waiting comes with a payoff: the flavor is built in layers and the result is a deeply satisfying pot of soup.
Spiced Squash & Lentil Soup with Caramelized Onion and Fennel
This started as an Alison Roman idea and then I did what I always do: adjusted it until it felt like mine.
I love a dish that comes with a built-in complete meal: carbs, protein, vegetables, and fresh herbs. This Spiced Squash & Lentil Soup with Caramelized Onion and Fennel has all of that. Like most soups, it’s incredibly flexible and customizable, from the squash to the spices to the toppings.
One recipe is enough to feed a crowd, or stored in the freezer, it can last for the whole winter. It’s the kind of soup that needs a little dressing to look more interesting, but once you’ve adorned it with all the bells and whistles, it becomes a feast for the eyes, and the compliments won’t stop until the last bite has been scraped off the plate. You’ll be rattling off the ingredient list and method to everyone who’s lucky enough to try it – trust me.
Step‑by‑Step Overview
- Warm your aromatics: In a large pot, heat olive oil over medium low heat. Add sliced fennel and onions with a pinch of salt, and cook until caramelized. This is where the base flavor begins to build.
- Bloom your spices: Stir in cumin, red pepper flakes, and any other warm spices. Let them sizzle briefly to release their aroma – it’s what gives this spiced squash & lentil soup its depth.
- Cook the squash: Add your squash pieces, stirring to coat them in the fat and spices, and cook until the squash starts to break down, forming a coarse mash. The longer it cooks, the sweeter and more concentrated the flavor.
- Add lentils and liquid: Pour in your lentils and broth. Season lightly with salt and pepper. Bring to a gentle simmer and cook until the lentils are tender and the squash is fully softened, about 30–35 minutes.
- Finish with acid and herbs: Just before serving, stir in a splash of lemon juice or vinegar to brighten the flavors. Top with fresh herbs and a drizzle of olive oil. Add the caramelized onion and fennel.
- Serve and enjoy: This spiced squash & lentil soup can be eaten immediately, stored in the fridge for a few days, or frozen for a quick winter meal. Garnish generously for a feast-worthy presentation.
Make It Yours
Vegan: Although this soup is entirely vegan, I like topping mine with sour cream. You can just skip it or add a dairy-free alternative.
Herbs: Fresh dill and cilantro are my favorite options, but parsley, chives, or scallions are also great additions. Just make sure to add a generous amount; the fresh herbs really brighten up the soup.
Swap spices: For a more warm and sweet soup, a little bit of cinnamon, nutmeg, and ginger would work well here. For a more earthy flavor, sage, thyme, oregano, and paprika work well with the cumin.
Other toppings: Instead of sour cream, you can top the soup with a dollop of crème fraîche or a drizzle of heavy cream. And don’t forget to save some of the caramelized onion and fennel for the topping; it makes it even better!
What to Serve With It
Bread: A crusty loaf works best — something you can tear or dip into the soup. A baguette, rustic country bread, or even a sturdy sandwich bread will do.
Salad: A bright, acidic salad cuts through the richness of the soup. Think mixed greens with lemon vinaigrette, arugula with olive oil and a pinch of sea salt, or a simple cabbage slaw.
Protein: This soup is hearty on its own, but if you want to add a protein, roasted chicken, seared fish, or baked tofu are all easy options.
Drinks: Keep it cozy or celebratory – a crisp white wine, dry rosé, sparkling water with lemon, or even a spiced cider or mulled wine in winter.
Notes from My Small Kitchen
You can use any squash you have on hand for this, but the mild, tender acorn squash is the superior choice here. Part of what makes this soup so great is how the squash sautés and browns in the pan for a long time, until it begins to fall apart.
As it cooks in the broth, it softens and becomes buttery, creating a thick, creamy soup without the need for any additional aid, like a blender.
You Might Also Like…
Roasted Butternut Squash and Tomato Soup: If you’re in the mood for another cozy bowl with a little more brightness, this roasted butternut squash and tomato soup hits that sweet spot between rich and fresh.
Chicken Pot Pie Soup: When you want comfort food that actually feels like dinner, this chicken pot pie soup delivers all the nostalgia with far less effort.
Chicken and Leek Soup: Simple, classic, and deeply soothing, chicken and leek soup is the kind of thing you make when you want something quiet and reliable on the stove.
Citrus Salad with Fennel and Radish: For something crisp and refreshing to balance all that warmth, this citrus salad with fennel and radish brings brightness and bite to the table.
Spiced Squash & Lentil Soup with Caramelized Onion and Fennel
4-6
servings20
minutes1
hour 20 minutesIngredients
4 tablespoons olive oil, plus more
2 medium yellow onions, thinly sliced
1 fennel bulb, thinly sliced
Kosher salt
Freshly ground black pepper
1 tsp ground cumin
½ tsp chili powder
1 small acorn, kabocha, or butternut squash (1¾–2 pounds), peeled, seeded, cut into 1-inch pieces
4 garlic cloves, thinly sliced
1½ cups red or yellow lentils
8 cups vegetable or chicken broth
2 tsp white wine vinegar, plus more
2 cups coarsely chopped mixed herbs, such as cilantro, dill, chives, and/or scallions
Yogurt or sour cream, for serving
- Equipment:
Directions
Heat the olive oil in a large pot over medium heat. Add the onion and fennel, and season with salt and pepper. Cook, stirring occasionally, until caramelized (this will take you at least 30 minutes; add a splash of water or broth every now and then for a better and quicker browning).
Stir in the cumin and chili powder and cook for another minute or two, just until the spices bloom in the fat and become fragrant. Using a slotted spoon or fork, remove about half of the caramelized onions and fennel and set them aside for topping.
Add the squash and garlic to the pot and season again with salt and pepper. Cook, stirring occasionally, until the garlic is tender and the squash begins to break down into a very coarse mash, about 15–20 minutes.
Add the lentils along with the broth and season with salt and pepper. Bring to a gentle simmer and cook until the lentils are tender and the squash has melted into the broth, about 30–35 minutes. The soup should be creamy and thick, similar to split pea soup — not fully smooth, but with small pieces of squash throughout. If it seems too thin, continue simmering until the texture suits you.
To serve, stir in the white wine vinegar and adjust seasoning with more salt and pepper as needed; the soup should have enough acidity to balance the sweetness of the squash. Ladle into bowls and top with the reserved onions, yogurt or sour cream, herbs, a drizzle of olive oil, and a final grind of black pepper.
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