Celeriac Soup With Hazelnut Crumble

There's something almost magical about how celeriac transforms when it hits the oven—that earthy, slightly bitter root vegetable becomes impossibly sweet and nutty once roasted. I stumbled onto this soup on a gray afternoon when I had half a celeriac sitting in my crisper drawer, wondering what to do with it. The combination of velvety pureed vegetables with that unexpected crunch of toasted hazelnuts felt like discovering a secret that had been waiting in my kitchen all along.

I made this for my sister last winter when she was visiting on a particularly cold evening, and watching her face light up when she tasted it made me realize I'd created something special. She's not usually one for vegetable soups, but she went back for seconds and asked for the recipe before she left. That moment told me this wasn't just comfort food—it was the kind of dish that makes people feel genuinely cared for.

Ingredients

• Celeriac (700 g, peeled and diced): This is the star, and roasting it transforms its earthy nature into something almost sweet; don't skip the browning step as it makes all the difference.
• Medium onion and garlic (diced and minced): The aromatic base that builds flavor, and sautéing them first coaxes out their sweetness before the broth goes in.
• Medium potato (150 g, peeled and diced): This adds body and creaminess to the soup, which means you can use less cream if you prefer.
• Vegetable broth (900 ml): Use a good quality broth you'd actually drink on its own; weak broth means weak soup, so don't economize here.
• Olive oil (2 tbsp total): One tablespoon for roasting the celeriac, one for sautéing—this keeps everything tasting clean and bright.
• Heavy cream (100 ml, optional): The optional part is genuine; if you want a lighter soup, skip it entirely or use just a splash for richness.
• Sea salt (1 tsp) and black pepper (1/2 tsp): Always taste before seasoning fully, as your broth might already carry salt.
• Ground nutmeg (1/4 tsp): Just a whisper of nutmeg—this isn't a dessert, and less is truly more with this spice.
• Whole hazelnuts (60 g): Buy them whole and toast them yourself; pre-chopped ones lose their oils and fragrance by the time you use them.
• Unsalted butter (1 tbsp) or olive oil for vegan: The butter toasts the nuts beautifully, bringing out their natural sweetness and creating that irresistible crunch.
• Fresh parsley (1 tbsp, finely chopped): Add this after toasting to preserve its bright green color and fresh flavor.

Instructions

Roast the celeriac until golden:

Preheat your oven to 200°C and spread the diced celeriac on a baking sheet with a drizzle of olive oil, tossing it around with your hands so every piece gets coated. Roast for 25 to 30 minutes, turning it once halfway through, until the edges are caramelized and golden—this is where the magic happens.

Sauté your aromatic base:

While the celeriac roasts, warm olive oil in a large pot over medium heat and add your diced onion and minced garlic, stirring occasionally until they're soft and smell incredible, about 3 to 4 minutes. You're building flavor here, so don't rush it or turn the heat too high.

Combine and simmer until tender:

Add the roasted celeriac and diced potato to the pot, pour in your vegetable broth, and bring everything to a boil before reducing the heat to a gentle simmer for 15 to 20 minutes. The vegetables should be so soft they fall apart easily when you stab them with a fork.

Toast the hazelnuts while you wait:

In a small skillet over medium heat, melt the butter and add your roughly chopped hazelnuts, toasting them for 2 to 3 minutes until they smell absolutely toasted and fragrant. Stir in the fresh parsley and a pinch of salt, then set this aside to cool slightly.

Blend until completely smooth:

Using an immersion blender, puree the soup right in the pot until it's silky and velvety with no chunks remaining. If you're using a stand blender, work in batches and be careful with the hot liquid, always leaving the lid slightly ajar for steam to escape.

Season and finish:

Stir in the cream if you're using it, add the nutmeg, and taste carefully before adding salt and pepper—remember that your broth already contained sodium. A gentle reheat over low heat is all you need if the soup has cooled slightly.

Serve with celebration:

Ladle the soup into warm bowls and sprinkle that toasted hazelnut crumble generously over the top, letting some of it sink into the warmth and some stay crunchy on the surface. Serve immediately while everything is at its best.

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There was a morning last spring when a friend came over unannounced, and I made this soup while she sat at my kitchen counter drinking coffee. By the time we sat down to eat, the kitchen smelled like toasted hazelnuts and roasted earth, and somehow that simple act of cooking alongside someone turned an ordinary Wednesday into something I still think about. Food becomes memory when it's made with intention and served with warmth.

Why Roasting Matters More Than You Think

The difference between a roasted celeriac soup and a boiled one is genuinely night and day, and it's the kind of cooking principle that applies to so much more than just this recipe. When you roast vegetables, you're coaxing out their natural sugars through heat, creating caramelization that brings sweetness and depth. I learned this the hard way by making the boiled version first, tasting how thin and one-dimensional it was, then roasting the next batch and being completely shocked by the transformation—that's when I understood that good cooking isn't about complexity, it's about respecting your ingredients and giving them the right conditions to shine.

The Hazelnut Crumble—Your Secret Weapon

This crumble is so simple that it feels almost too easy to matter, but it's actually the difference between a soup that feels complete and one that leaves you wanting something. The toasted hazelnuts add warmth and richness, the parsley brings brightness, and the butter creates that crispy, buttery coating that makes you want to scrape the bottom of the bowl. I've noticed that people eat significantly more of this soup when the crumble is generous, which tells you something about texture and how our mouths need variety, even in something as comforting as soup.

Storage, Leftovers, and Serving Ideas

This soup keeps beautifully for three or four days in the refrigerator in an airtight container, and it actually tastes deeper the next day as the flavors continue melding. Reheat gently over low heat with a splash of broth or cream if it thickens too much, and always make the hazelnut crumble fresh just before serving so it stays crunchy.

• Drizzle with hazelnut oil or a swirl of white truffle oil for an unexpectedly elegant finish.
• Serve alongside crusty bread for dipping, or with a simple green salad to balance the richness.
• Pairs wonderfully with a crisp Sauvignon Blanc or a light Pinot Grigio if you're making an evening of it.

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This soup reminds me that the best meals don't require show-off ingredients or complicated techniques—they just require attention and care. Make it, share it, and watch how something so simple becomes something people remember.

Recipe Help & FAQs

→ Can I make this soup ahead of time?

Yes, the soup keeps beautifully in the refrigerator for up to 4 days. Store the hazelnut crumble separately in an airtight container to maintain crunchiness, then sprinkle over each serving when reheating.

→ What can I substitute for celeriac?

Cauliflower or parsnips make excellent alternatives, offering similar creamy texture when blended. Adjust roasting time as needed—cauliflower may cook faster than celeriac.

→ How do I make this vegan?

Simply swap the heavy cream for coconut cream or cashew cream, and use olive oil instead of butter for toasting the hazelnuts. The soup remains equally rich and satisfying.

→ Can I skip roasting the celeriac?

While you can simmer it directly, roasting significantly deepens the flavor by caramelizing the natural sugars. This step is highly recommended for the best taste experience.

→ What other nuts work for the crumble?

Toasted almonds, walnuts, or pecans are wonderful alternatives. Each brings its own unique flavor profile—walnuts add earthiness while pecans offer buttery sweetness.

→ How can I adjust the consistency?

For a thinner soup, add more vegetable broth during blending. For extra richness and body, increase the cream or add an extra potato to the base.