Celeriac Soup with Hazelnut Crumble

There's something about celeriac that catches people off guard—that knobbly, pale root vegetable sitting alone in the produce section, looking almost intimidating. I discovered its magic quite by accident when a farmer's market vendor handed me one with a knowing smile and whispered that roasting would transform it into something completely unexpected. That first bowl, with its creamy earthiness and that satisfying crunch of toasted hazelnuts on top, made me realize I'd been missing out on one of autumn's best-kept secrets.

I made this for a dinner party on a chilly October evening when the conversation had been lagging, and something shifted the moment I brought out those steaming bowls topped with golden nuts. My friend Sarah, who usually doesn't eat much at dinner parties, asked for seconds and spent the rest of the evening asking about celeriac—where to find it, how to store it, whether she could make it at home. That's when I knew this recipe had legs.

Ingredients

• Celeriac (about 700 g): This bumpy root is pure umami when roasted; peeling it takes a bit of patience, but a sharp knife and steady hands make quick work of it.
• Potato (about 150 g): Just enough to add body and help the soup reach that silky consistency without making it feel starchy.
• Onion and garlic: The aromatic foundation that builds flavor while the celeriac roasts—don't skip the sauté step, as it sets the tone for everything else.
• Vegetable broth (900 ml): Use a good quality broth you'd actually drink on its own; the soup only tastes as good as your base.
• Heavy cream or plant-based alternative (100 ml): A whisper of richness that rounds out the earthiness—optional, but it does make a difference.
• Ground white pepper: More delicate than black pepper, it won't speckle the pale soup and lets the hazelnut flavor shine.
• Hazelnuts (70 g): Whole nuts that you'll toast yourself taste incomparably better than pre-chopped; that toasty aroma filling your kitchen is part of the experience.
• Butter and sea salt for the crumble: Toast the hazelnuts in their own fat so they become golden and cling together just enough.

Instructions

Prepare and roast the celeriac:

Heat your oven to 200°C and toss those cubed celeriac pieces with olive oil, salt, and pepper on a baking tray. Watch them turn golden and caramelized over 25 to 30 minutes, turning them halfway through so they roast evenly from all sides.

Build the aromatics:

While the celeriac works its magic in the oven, warm olive oil in a large pot and let the chopped onion soften and turn translucent over about four minutes. Add minced garlic and diced potato, cooking for just two more minutes until the kitchen smells incredible.

Combine and simmer:

Scrape the roasted celeriac into the pot with the aromatics, pour in your vegetable broth, and bring everything to a gentle boil before settling it into a quiet simmer. Let it bubble away for 15 to 20 minutes until all the vegetables are tender enough to break apart with a spoon.

Toast the hazelnut crumble:

In a separate skillet over medium heat, toast the whole hazelnuts dry for three to four minutes, listening for them to become fragrant and watching for a deeper color. Add butter and sea salt, stirring constantly so the nuts get evenly coated and turn a rich golden brown before you remove them from heat.

Blend until silky:

Using an immersion blender, work through the soup until it transforms into something velvety and smooth with no visible chunks. If you're using a countertop blender, work in batches and be careful with the hot liquid, letting each batch cool slightly before blending the next.

Finish with cream and seasoning:

Stir in the cream if you're using it, then taste and adjust the salt and white pepper until it feels balanced. Sometimes just a pinch more salt makes all the difference between good and unforgettable.

Serve and garnish:

Ladle the soup into bowls and pile that hazelnut crumble generously on top, finishing with a scatter of fresh parsley if you have it. The contrast between the warm, creamy soup and the crunchy, buttery nuts is where the real magic happens.

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There was a quiet moment during that October dinner when everyone was eating in comfortable silence, spoons clinking against bowls, and I realized that sometimes the best meals don't need much fanfare—just honest ingredients treated with a little intention. This soup has a way of doing that, making people slow down and actually taste what they're eating.

The Magic of Roasting

Roasting vegetables might seem like an extra step, but it's where flavor concentrates and deepens. The celeriac caramelizes at the edges, its natural sugars intensify, and you end up with something that tastes nothing like raw celeriac—this is the entire reason the soup works so well. I learned this through a mistake, actually; I once tried to make the soup without roasting and ended up with something pale and forgettable that I wouldn't serve to anyone.

Playing with Texture

A smooth soup needs something to push against texturally, which is why that hazelnut crumble matters so much. Some people want more crunch, so they add it directly into the soup; others prefer to keep it on top so each spoonful is a surprise. The beauty of this recipe is that you can adjust it to your own preference without changing the core of what makes it work.

Variations Worth Trying

Once you've made this soup a few times, you'll start seeing possibilities everywhere. A squeeze of fresh lemon juice brightens everything right before serving, fresh thyme stirred into the warm soup adds an herbal note that feels very European, and some people swear by a tiny splash of white wine added to the aromatics stage. Here are a few easy tweaks that keep the recipe fresh:

• Add a sprig of fresh thyme to the broth as it simmers, then fish it out before blending for a subtle herbal backbone.
• Stir in a squeeze of fresh lemon or a teaspoon of sherry vinegar at the very end to brighten the earthy flavors.
• Toast some fresh sage leaves in the butter alongside the hazelnuts for a different kind of depth.

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This soup has quietly become one of my go-to dishes when I want to feel like I'm cooking something special without the stress. It's the kind of recipe that rewards you for paying attention but forgives you if you don't.

Recipe FAQs

→ What does celeriac taste like?

Celeriac has a mild, earthy flavor with subtle celery notes and a hint of sweetness. When roasted, these qualities deepen and become more pronounced, making it an excellent base for creamy soups.

→ Can I make this soup ahead of time?

Absolutely. The soup base can be prepared up to 2 days in advance and refrigerated. Store the hazelnut crumble separately in an airtight container. Reheat gently on the stove, adding a splash of broth or cream if needed to adjust consistency, then top with fresh crumble before serving.

→ How do I achieve the smoothest texture?

Roasting the celeriac first softens it completely, which helps create a silky purée. Use an immersion blender for several minutes, or work in batches with a high-speed countertop blender. For extra refinement, pass the blended soup through a fine-mesh sieve.

→ What can I substitute for hazelnuts?

Walnuts, pecans, or toasted almonds work beautifully as alternatives. Each brings its own character—walnuts add slight bitterness, pecans contribute sweetness, while almonds offer a more neutral crunch. The toasting and butter-coating technique remains the same.

→ Is this soup suitable for freezing?

Yes, the soup freezes well for up to 3 months. Cool completely before transferring to freezer-safe containers, leaving some space for expansion. Thaw overnight in the refrigerator and reheat gently. Prepare fresh hazelnut crumble when serving, as it doesn't maintain its texture after freezing.

→ How can I add more protein?

Stir in white beans or lentils during the simmering stage for a protein boost. Alternatively, serve with crusty bread and cheese, or top with toasted pumpkin seeds alongside the hazelnuts for extra plant-based protein.