Celeriac Soup With Hazelnut Crumble

There's something about autumn that makes me crave soup, and this celeriac soup landed in my kitchen by accident—I'd bought a massive root vegetable at the farmers market without a real plan, then remembered a friend mentioning how roasting it first changes everything. That golden, caramelized flavor turned what could've been ordinary into something I now make whenever I need comfort in a bowl. The hazelnut crumble on top was an afterthought, honestly, but it became the reason people ask for seconds.

I made this for a dinner party once when I was still figuring things out in the kitchen, and I remember being genuinely nervous about serving soup as a first course—somehow it felt less impressive than pasta. But watching people's faces when they tasted it, when that crunch of hazelnuts hit their spoon, I realized comfort food doesn't need to apologize. It just needs to be honest and delicious.

Ingredients

• Celeriac (about 700 g): This knobby root vegetable is the star, and roasting it first is non-negotiable—it concentrates the flavors and creates that deep, almost caramel-like sweetness.
• Potato (about 150 g): It adds body and helps the soup feel naturally creamy when blended, without needing cream to do all the work.
• Onion and garlic: The aromatic foundation that softens into the background, letting the celeriac shine.
• Vegetable broth (900 ml): Use good quality broth—it matters more here than in busier dishes where flavors compete.
• Heavy cream or plant-based alternative (100 ml): Optional, but it adds a luxurious mouthfeel; feel free to skip it if you prefer a lighter soup.
• Olive oil: Both for roasting and sautéing, it's the supporting actor that keeps everything tasting fresh.
• Sea salt, black pepper, and ground nutmeg: The nutmeg is the secret ingredient that rounds out the earthiness—use just a whisper of it.
• Hazelnuts (60 g): Whole nuts that you'll chop roughly and toast, bringing texture and a toasted richness that defines this soup.
• Butter and fresh parsley: For the crumble, the butter toasts the nuts to golden perfection while parsley adds a bright, fresh contrast.

Instructions

Roast the celeriac until it caramelizes:

Preheat your oven to 200°C (400°F) and spread the diced celeriac on a baking sheet with a light drizzle of olive oil, turning it once halfway through. You'll know it's ready when the edges turn golden and it smells almost sweet—around 25 to 30 minutes.

Build the flavor base in your pot:

Heat olive oil in a large pot and soften the onion and garlic for a few minutes until fragrant and translucent. This creates the foundation where all the other flavors will live.

Combine and simmer until everything softens:

Add the roasted celeriac and diced potato to the pot, pour in the vegetable broth, and bring everything to a gentle boil. Then lower the heat and let it simmer for 15 to 20 minutes—the vegetables should be completely tender when you press them with a spoon.

Toast the hazelnuts while the soup cooks:

Roughly chop your hazelnuts and toast them in butter in a small skillet over medium heat until they're golden and smell incredible, about 2 to 3 minutes. Stir in the fresh parsley and a pinch of salt, then set aside.

Blend the soup until it's silky smooth:

Using an immersion blender directly in the pot, puree everything until you have a completely smooth, velvety texture. If you're using a stand blender, work in batches and be careful with the hot liquid.

Finish with cream and seasonings:

Stir in the cream (if you're using it), a quarter teaspoon of nutmeg, and salt and pepper to taste. Give it a gentle reheat if needed, letting the flavors marry together.

Serve with the hazelnut crumble:

Ladle the soup into warm bowls and crown each one generously with the toasted hazelnut mixture. The contrast between the silky soup and crunchy topping is what makes this dish feel complete.

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What I didn't expect was how this soup became a way to use up that slightly sad bag of hazelnuts my mother brought over, or how it transformed a quiet Tuesday night into something that felt intentional and warm. Food has a way of becoming a conversation when it tastes like someone actually cared.

Why Roasting Makes All the Difference

The first time I tried making celeriac soup without roasting the vegetable first, I understood why so many people think root vegetables are boring. Roasting concentrates the natural sugars and deepens the flavor profile in ways boiling simply cannot match—it's the difference between a soup that tastes like something and a soup that tastes like potential. The golden edges on the celeriac pieces are doing actual flavor work, not just looking pretty.

Cream is Optional, But Texture is Everything

I've made this soup both ways, and while it's delicious without cream, adding it creates a mouthfeel that makes the soup feel like a proper course rather than a side. If you're keeping it vegan or lighter, the potato does enough blending to give you creaminess without added fat—but if you have cream on hand, use it. There's a reason French soups taste the way they do.

Making it Your Own at the Table

Once you've made this soup a few times, it becomes a blank canvas for whatever you have in your pantry or what's calling to you that day. I've served it with crispy sage leaves, a drizzle of truffle oil, extra pepper, and even some toasted breadcrumbs when I was out of hazelnuts. The soup itself is the steady foundation—the toppings are where you tell your own story.

• Crusty bread on the side transforms this from a first course into a full meal that feels intentional.
• A crisp white wine like Sauvignon Blanc cuts through the richness and brings out the nutmeg's subtle spice.
• Fresh herbs scattered on top at the very last second add brightness and make it feel like you've taken an extra moment to care.

Save

This soup has become the kind of recipe I make when I want to feel like I'm taking care of someone, including myself. It asks for time and attention, but rewards you with something that tastes like autumn and comfort in equal measure.

Recipe FAQ

→ Can I make this soup vegan?

Yes, simply replace the heavy cream with plant-based cream (coconut, oat, or cashew work well) and use olive oil instead of butter for the hazelnut crumble.

→ Why roast the celeriac before blending?

Roasting caramelizes the celeriac's natural sugars, creating deeper, sweeter flavors and eliminating any bitterness. It transforms the vegetable from sharp to mellow and nutty.

→ Can I prepare the hazelnut crumble in advance?

Yes, toast the hazelnuts up to 2 days ahead and store in an airtight container. Add the fresh parsley just before serving to maintain its bright color and flavor.

→ What can I substitute for celeriac?

Cauliflower or parsnips make excellent substitutes, offering similar creamy texture when blended. Adjust seasoning as these vegetables have milder flavors than celeriac.

→ How do I store leftover soup?

Store the soup and crumble separately in airtight containers in the refrigerator for up to 3 days. Reheat soup gently on the stovetop and add fresh crumble when serving.

→ Can I freeze this soup?

Yes, freeze the soup base without cream for up to 3 months. Thaw overnight in the refrigerator, reheat, then stir in fresh cream and prepare the hazelnut crumble just before serving.