Celeriac Soup With Hazelnut Crumble

The first time I roasted celeriac instead of boiling it, everything changed. A friend had left a bulbous, knobby root on my counter with a cryptic note: try this differently. What emerged from the oven was golden, almost caramelized, nothing like the pale mush I'd made before. That afternoon, I blended it into silk and topped it with buttery hazelnuts still crackling from the skillet, and suddenly soup felt like something worth getting excited about.

Years later, I made this for a dinner party on a gray November evening when everyone arrived looking tired. By the time I ladled bowls and scattered those golden hazelnuts on top, the whole table seemed to exhale. It wasn't fancy or complicated, but there was something about the warmth and texture that made people linger over spoons instead of rushing through courses.

Ingredients

• Celeriac (700 g), peeled and diced: This knobbly root is the star, and roasting it brings out a subtle sweetness that makes the cream almost unnecessary.
• Potato (150 g), peeled and diced: Acts as a gentle thickener and adds body without overwhelming the delicate celeriac flavor.
• Onion and garlic (1 medium onion, 2 cloves): Sautéed first to build a savory base that balances the earthiness of the root vegetables.
• Vegetable broth (900 ml): Use something good here, since it's the liquid backbone of the entire soup.
• Heavy cream (100 ml, optional): Swirl it in at the end for silk, or skip it entirely if you prefer the soup leaner and more mineral tasting.
• Olive oil (2 tbsp total): One tablespoon roasts the celeriac, one starts the aromatics, and it keeps everything moving smoothly.
• Sea salt, black pepper, ground nutmeg: Salt and pepper are your regulars, but nutmeg is the quiet voice that makes people ask what the secret ingredient is.
• Hazelnuts (60 g, whole): Toast these just until fragrant, because burnt nuts can't be salvaged and they'll haunt your bowl.
• Unsalted butter (1 tbsp): For the hazelnut crumble, it creates a gentle toast without browning too fast.
• Fresh parsley, finely chopped: A small handful stirred into the warm nuts brings brightness that cuts through the richness.

Instructions

Roast the celeriac:

Preheat your oven to 200°C and scatter diced celeriac on a baking sheet, tossed with olive oil. Let it roast for 25 to 30 minutes, stirring halfway, until the edges turn golden and it yields easily to a fork. The smell alone will tell you when it's ready, nutty and almost caramelized.

Start the soup base:

While the oven does its work, warm a large pot with olive oil over medium heat and sauté your diced onion and minced garlic for 3 to 4 minutes until softened and fragrant. This foundation catches the heat and releases everything you'll taste later.

Build the broth:

Add the roasted celeriac and diced potato to the pot, then pour in your vegetable broth and bring everything to a boil. Reduce the heat and let it simmer gently for 15 to 20 minutes, until the vegetables break apart at the gentlest prod.

Toast the hazelnut crumble:

While soup simmers, roughly chop your hazelnuts and melt butter in a small skillet over medium heat, then add the nuts and toast for 2 to 3 minutes, stirring often, until they smell warm and golden. Remove from heat and stir in your chopped parsley and a small pinch of salt, then let it cool slightly so the nuts stay crunchy.

Blend to silky smoothness:

Once the vegetables are completely tender, use an immersion blender to puree the soup directly in the pot, or work in batches with a stand blender if you prefer. You want it completely smooth, with no grainy texture left behind.

Season and finish:

Stir in the cream if you're using it, then add the nutmeg, salt, and pepper to taste. Reheat gently if needed, but don't let it boil or the cream will separate.

Serve with ceremony:

Ladle the hot soup into bowls and scatter the hazelnut crumble generously across the top. Watch it sit on the warm surface, nuts crunching when you dig in.

Save

The best part of this soup isn't the ingredients or even the technique. It's the moment when someone dips their spoon through the hazelnut crumble and finds that velvety warmth underneath, and their face softens.

Why Roasting Changes Everything

Boiled celeriac tastes like wet chalk, which sounds dramatic but is honestly accurate. Roasting it develops the natural sugars and adds a gentle bitterness that makes the soup taste intentional instead of accidental. The heat also concentrates the flavor, so you need less broth and less cream to feel satisfied, which means the pure taste of the vegetable comes through.

The Hazelnut Crumble Strategy

There's something about adding texture to soup that transforms it from a side dish into the main event. The crumble isn't just decoration, it's your excuse to slow down and notice the contrast between creamy and crunchy, hot and cool. A lot of people skip this step to save time, but honestly, it's worth the extra five minutes because it's where the magic lives.

Adaptations and Mood Swings

On nights when you're too tired for cream, skip it and add an extra splash of broth instead, and the soup will taste cleaner and more mineral. If hazelnuts aren't in your pantry, toasted almonds or walnuts work just as well, though they'll change the personality slightly. This soup is flexible enough to meet you where you are, whether you're vegan, tired, or just having a day where richness doesn't sound appealing.

• Drizzle with hazelnut oil at the very end if you want to push the nuttiness further and impress yourself.
• Pair this with crusty bread that's still warm from the bakery, or stay simple with just a spoon and a bowl.
• Make a double batch and freeze the soup base without the crumble, then top with fresh nuts when you reheat it days later.

Save

This soup became a regular in my kitchen because it asks so little but gives so much. Make it once and you'll understand why celeriac deserves better than obscurity.

Recipe Q&A Section

→ What does celeriac taste like?

Celeriac has a subtle, earthy flavor with mild celery notes and a hint of sweetness. When roasted, it develops a deeper, nuttier taste that pairs wonderfully with cream and spices.

→ Can I make this vegan?

Absolutely. Simply replace the heavy cream with your favorite plant-based alternative and use olive oil instead of butter in the crumble. The result remains just as creamy and satisfying.

→ How should I store leftovers?

Keep cooled soup in an airtight container in the refrigerator for up to 3 days. Store the hazelnut crumble separately in a sealed bag or jar to maintain its crunch. Reheat gently on the stove.

→ 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 cream. The hazelnut topping is best made fresh.

→ What can I serve with this?

Crusty bread or artisanal rolls make perfect dippers. A crisp white wine like Sauvignon Blanc complements the earthy flavors. A simple green salad with vinaigrette balances the richness beautifully.