Celeriac Hazelnut Crumble

There's something about roasted celeriac that catches you off guard the first time you smell it—earthy and almost sweet, nothing like the raw root vegetable sitting in your crisper drawer. I discovered this soup on a grey afternoon when I had a large celeriac staring at me and absolutely no idea what to do with it. A friend mentioned roasting it first, and that simple shift transformed what I thought would be a bland, forgettable soup into something I now make whenever I want to feel like I've discovered a kitchen secret.

I made this for my partner on a night when neither of us felt like thinking too hard about dinner, and watching his face when he tasted it—genuinely surprised by how much depth was hiding in something so simple—made me realize this was the kind of recipe worth keeping close. He asked for it again the next week, which is when I knew I'd stumbled onto something good.

Ingredients

• Celeriac (about 700 g): The star ingredient, and honestly, roasting it is non-negotiable—it mellows the earthiness and brings out a subtle sweetness that boiling alone never achieves.
• Onion and garlic: These build the flavor base while the celeriac roasts, creating a aromatic foundation that makes the whole kitchen smell inviting.
• Potato (about 150 g): This adds body and creaminess to the soup without needing excessive cream, which I learned matters more than I expected.
• Vegetable broth (900 ml): Use something with actual flavor—it makes a noticeable difference in the final taste.
• Olive oil (2 tbsp total): Split between roasting the celeriac and sautéing the aromatics; don't skimp here.
• Heavy cream or plant-based alternative (100 ml): Optional but highly recommended—it smooths out the earthiness and makes the soup feel luxurious.
• White pepper and salt: White pepper keeps the soup visually pure, but black pepper works just fine if that's what you have.
• Hazelnuts (70 g): Chopped roughly so some pieces stay distinct in your bite; the toasting brings out their natural richness.
• Butter or margarine (1 tbsp): This coats the hazelnuts and keeps them from tasting dry, creating that irresistible crunch.
• Parsley: A light garnish that adds a whisper of freshness against the deep, earthy soup.

Instructions

Get your oven ready:

Preheat to 200°C (390°F) and give it a few minutes to fully heat while you prep the vegetables.

Roast the celeriac:

Toss the cubes with 1 tbsp olive oil, salt, and pepper, then spread them out on a baking tray in a single layer. You want them to have space to roast, not steam—this is where the magic happens. Roast for 25–30 minutes, turning halfway through, until the edges are golden and the insides are tender enough to break with a fork.

Build the base while waiting:

Heat the remaining olive oil in your pot over medium heat, add the chopped onion, and let it soften for about 4 minutes until it turns translucent. Add the garlic and potato, cooking just long enough for the raw garlic smell to fade, which takes roughly 2 minutes.

Combine and simmer:

Once the celeriac comes out of the oven, add it to the pot along with the vegetable broth. Bring the whole thing to a gentle boil, then lower the heat and simmer for 15–20 minutes until every vegetable is so soft it practically falls apart when you touch it with a spoon. This is the moment you know it's ready—no resistance, just silky tenderness.

Toast the hazelnuts:

While the soup simmers, put your hazelnuts in a dry skillet over medium heat and toast for 3–4 minutes, stirring occasionally, until they smell absolutely incredible and start turning golden. Add the butter and sea salt, stirring until every nut is coated and glistening, then pour onto a plate to cool. They'll crisp up as they cool, which is exactly what you want.

Blend until silky:

Using an immersion blender, purée the hot soup right in the pot, working until there are no visible chunks and the texture is completely velvety. If you're using a countertop blender, work in batches and be careful with the heat—never fill it more than halfway. Stir in the cream (if using), taste, and adjust the seasoning with salt and white pepper until it feels right to you.

Finish and serve:

Ladle the soup into bowls and top each one generously with the hazelnut crumble, letting some pieces catch the light. Scatter parsley over top and serve while the soup is still steaming and the nuts are still crisp.

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The moment I realized this soup was special came when someone asked me for the recipe and then made it for their own dinner party. They came back and told me their guests actually asked what was in it, which feels like the highest compliment a simple soup can receive.

Why Roasting Changes Everything

Raw celeriac is pale and slightly bitter, the kind of vegetable you have to work to appreciate. But roast those cubes until they're caramelized at the edges? They become something else entirely—sweeter, deeper, almost nutty. I learned this by accident when I had no energy to prep it properly and threw it in the oven out of laziness, and that accident became the foundation of the whole recipe.

The Role of the Crumble

Without the hazelnut topping, this is a nice, quiet soup—good for a simple lunch or a light dinner. But that crumble transforms it into something more interesting, something with texture and complexity. The contrast between the smooth, velvety soup and the crisp, buttery nuts is the whole reason I make this instead of just any roasted vegetable soup.

Variations and Personal Touches

Once you understand the bones of this recipe, it becomes a canvas for whatever you have on hand or whatever mood you're in. I've added fresh thyme when I wanted an herbaceous note, squeezed lemon juice when it felt too heavy, and even swapped the hazelnuts for toasted walnuts when that's what was in my pantry.

• A drizzle of good truffle oil on top elevates this from everyday to special occasion without much effort.
• Try stirring in a spoonful of Dijon mustard if you want an unexpected savory punch.
• For a lighter version, use vegetable broth alone or add less cream—the soup is forgiving enough to adapt to what you need.

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This soup has become my answer to that question of what to cook when you want something that feels both comforting and a little bit refined. It's the kind of recipe that reminds you why simple ingredients, treated with a little care, can be more satisfying than anything complicated.

Recipe Questions & Answers

→ Can I prepare the celeriac in advance?

Yes, you can roast the celeriac up to two days ahead and store it in the refrigerator. Simply reheat with broth before blending, and prepare the hazelnut topping fresh for optimal crunch.

→ What substitutions work for hazelnuts?

Toasted pecans, walnuts, or even pumpkin seeds make excellent alternatives if you need to avoid tree nuts. Each brings slightly different flavor notes while maintaining the desired texture contrast.

→ How do I achieve the smoothest texture?

Roasting the celeriac until completely tender is key, then blending thoroughly with an immersion blender. For ultra-smooth results, pass through a fine-mesh sieve after puréeing.

→ Can this dish be frozen?

The purée freezes beautifully for up to three months. However, prepare the hazelnut crumble fresh when serving, as freezing can compromise its delightful crispiness.

→ What wine pairs best?

A dry Pinot Gris or Chardonnay complements the earthy celeriac beautifully. The wine's subtle acidity cuts through the creamy texture while enhancing the nutty topping.