Save There's something about autumn that makes me crave soup, and this celeriac soup arrived in my kitchen almost by accident. I'd bought a knobby celeriac root at the farmers market, intending one thing, then got distracted by its earthy promise and decided to roast it instead. That decision changed everything—the sweetness that emerged from the oven was nothing like raw celeriac, and I knew I had to build something around it. The hazelnut crumble came later, a textural whim that turned out to be exactly what this silky soup needed.
I made this for my sister one rainy November afternoon when she stopped by unannounced. She'd had a rough week, and I remember the way her shoulders relaxed the moment she tasted it—that's when I realized this soup does something beyond nourish. The combination of warmth, texture, and that unexpected hazelnut finish somehow felt like a hug in a bowl, and she asked me to write down the recipe right there at the table.
Ingredients
- Celeriac (about 700 g), peeled and diced: This knobbly root vegetable becomes sweet and tender when roasted, developing a subtle nutty flavor that forms the soul of this soup.
- Medium onion, diced: Builds the aromatic base; the sweetness mellows as it cooks and supports the celeriac without overpowering it.
- Garlic (2 cloves), minced: A small amount keeps things subtle and elegant rather than aggressive.
- Medium potato (about 150 g), peeled and diced: Adds body and creaminess to the soup, helping achieve that silky texture even if you skip the cream.
- Vegetable broth (900 ml): Use a good quality broth you actually enjoy drinking, because it becomes the flavor foundation here.
- Olive oil (2 tbsp total): One portion for roasting the celeriac, one for sautéing; don't skip either step.
- Heavy cream (100 ml, optional): Adds richness, but the potato actually does most of the creaming work, so this is truly optional.
- Sea salt and freshly ground black pepper: Taste as you go; celeriac can be earthy, so seasoning generously makes all the difference.
- Ground nutmeg (1/4 tsp): Just a whisper of warmth that echoes the earthiness of the celeriac.
- Whole hazelnuts (60 g): These are what make the dish memorable; don't use pre-chopped or they'll lose their texture.
- Unsalted butter (1 tbsp): For toasting the hazelnuts until they're golden and fragrant, though olive oil works beautifully for vegan versions.
- Fresh parsley, finely chopped: A bright finish that cuts through the soup's earthiness and adds color.
Instructions
- Roast the celeriac until golden:
- Preheat your oven to 200°C and spread the diced celeriac on a baking sheet with 1 tablespoon of olive oil, tossing to coat evenly. Roast for 25 to 30 minutes, stirring halfway through, until the edges turn golden and the pieces feel tender when pressed. This step is crucial—it transforms celeriac from mild to subtly sweet.
- Build your aromatic base:
- While the celeriac roasts, warm the remaining tablespoon of oil in a large pot over medium heat and add your diced onion and minced garlic. Let them soften for about 3 to 4 minutes, stirring occasionally, until the kitchen smells deeply inviting.
- Combine and simmer:
- Add the roasted celeriac and diced potato to the pot along with your vegetable broth, bringing everything to a gentle boil. Reduce the heat and let it simmer quietly for 15 to 20 minutes until the vegetables are completely soft and break apart easily with a spoon.
- Toast the hazelnuts:
- While the soup simmers, roughly chop your hazelnuts (this is important—chunks toast better than slivers). Melt the butter in a small skillet over medium heat, add the hazelnuts, and toast for 2 to 3 minutes, stirring often, until they smell nutty and look golden brown. Remove from heat and stir in the parsley and a pinch of salt.
- Blend until silky:
- Once the vegetables are tender, use an immersion blender to puree the soup right in the pot, moving it around until you achieve a completely smooth, velvety texture. If you prefer using a stand blender, work in batches and return the soup to the pot.
- Season and finish:
- Stir in the cream if you're using it, along with the nutmeg, salt, and pepper, tasting as you go. Heat gently if needed, but don't boil, which can curdle the cream.
- Serve with the crumble:
- Ladle the hot soup into bowls and finish each one generously with the toasted hazelnut mixture, letting some nuts scatter across the surface for that delightful crunch.
Save There's a moment that happens every time I make this soup when someone takes that first spoonful and their eyes widen slightly—that instant when taste and texture surprise them in the best way. It's become my go-to when I want to cook something that feels thoughtful without demanding hours in the kitchen.
Why Roasting Changes Everything
Raw celeriac has an herbaceous, almost celery-like sharpness that can be polarizing, but roasting it mellows and sweetens the vegetable in a way that feels almost magical. The heat caramelizes the natural sugars, giving the finished soup depth and warmth without any added sweetness. I learned this by accident the first time I made it, and it's become the foundation of why people keep asking me to make it again.
The Hazelnut Difference
What makes this soup stand out from dozens of other roasted vegetable soups is that hazelnut crumble, which adds complexity most people can't quite name. Hazelnuts have this buttery, slightly sweet flavor that echoes the celeriac without competing with it, and they give you something to bite through after the smoothness of the soup. Many people assume you need elaborate garnishes for elegance, but a handful of toasted nuts and parsley does more work than you'd expect.
Making It Your Own
This recipe is forgiving enough to adapt to what you have on hand or what you're craving. I've made it with celery root and turnips together, swapped the hazelnuts for walnuts or almonds, and even drizzled hazelnut oil across the top for a gourmet finish that tastes like a fancy bistro. The core technique stays the same, but the variations are endless.
- If you can't find hazelnuts, walnuts or almonds toast beautifully and offer their own warm flavor.
- A small drizzle of truffle oil or hazelnut oil across each bowl takes this from weeknight comfort to special occasion worthy.
- Pair this with crusty bread and a crisp white wine like Sauvignon Blanc for a meal that feels both casual and celebratory.
Save This soup has become one of those recipes I make when I want to give someone comfort wrapped in elegance. It's the kind of dish that reminds you why cooking for others matters.
Kitchen Guide
- → Can I make this soup ahead of time?
Absolutely. The soup base actually improves after chilling overnight, allowing flavors to meld. Store it in the refrigerator for up to 3 days. Add the hazelnut crumble just before serving to maintain its crunch.
- → Is this soup freezer-friendly?
Yes, freeze the soup base without cream for up to 3 months. Thaw overnight, reheat gently, then stir in cream. The hazelnut crumble is best prepared fresh, though you can toast and store nuts separately for 1 week.
- → What can I substitute for hazelnuts?
Walnuts, pecans, or toasted pumpkin seeds work wonderfully. Each brings a slightly different nutty profile that still complements the earthy celeriac beautifully.
- → How do I achieve the smoothest texture?
Roasting the celeriac first is key—it breaks down fibers naturally. Blend thoroughly with an immersion blender for 2-3 minutes, or use a high-speed blender in batches. Straining through a fine mesh yields ultra-silky results.
- → Can I skip the cream?
The potato naturally thickens the soup, so cream is optional. For richness without dairy, try adding an extra potato or blending in a handful of cashews. The result remains satisfyingly creamy.
- → What bread pairs best?
Crusty sourdough, warm baguette slices, or whole-grain toast all provide excellent texture contrast. Lightly buttered or rubbed with garlic, they're perfect for soaking up every drop.