Celeriac with Hazelnut Crumble

I discovered celeriac soup quite by accident at a farmers market in late autumn, when a vendor handed me a knobbly root vegetable I'd never tried before and said, "Trust me, roast it." That single piece of advice changed how I think about forgotten vegetables. What struck me most was how the roasting transformed it—earthy, almost nutty, nothing like the raw vegetable I'd nervously brought home. The first bowl I made was eaten standing at the kitchen counter, steam rising into my face, and I remember thinking this needed something with crunch, something to push back against all that silky smoothness.

I made this for my sister last winter when she was recovering from a bout of flu, and she called me three days later just to ask for the recipe. She'd been living on bland broths, so I ladled this into her favorite bowl and watched her face change with that first spoonful. She said it tasted like comfort but also like I'd learned something in the kitchen she didn't know I knew, which made me smile because honestly, I was just following my instincts at that point.

Ingredients

• Celeriac (700 g, peeled and cubed): This knobby root vegetable becomes sweet and tender when roasted; don't be intimidated by its gnarly appearance because that's exactly what makes it special.
• Potato (150 g, peeled and diced): It acts as a subtle thickener and rounds out the earthiness without overpowering the delicate celeriac flavor.
• Onion (1 medium, chopped): The foundation of the soup, sautéed until translucent to build a gentle aromatic base.
• Garlic (2 cloves, minced): Just enough to whisper depth without shouting over the main ingredient.
• Vegetable broth (900 ml): Quality matters here—a good broth will make the whole soup sing where a weak one will leave it flat.
• Olive oil (2 tbsp): Part roasting fat, part cooking fat; it carries flavor and helps develop that golden crust on the celeriac.
• Heavy cream or plant-based alternative (100 ml): Optional but highly recommended, as it adds a luxurious finish that makes the soup feel like a proper meal.
• Ground white pepper (1/2 tsp): Milder than black pepper and it disappears into the soup rather than announcing itself.
• Sea salt: For seasoning the soup and, crucially, for toasting the hazelnuts so they taste vibrant.
• Hazelnuts (70 g, roughly chopped): The crumble's star—toasting them in butter is non-negotiable if you want that nutty, almost caramelized flavor.
• Unsalted butter or plant-based margarine (1 tbsp): The vehicle that turns toasted nuts into something memorable.
• Fresh parsley (1 tbsp, finely chopped): A bright finish that cuts through the richness; leave it out if you prefer pure earthiness.

Instructions

Heat your oven and prepare the celeriac:

Preheat to 200°C (390°F) while you peel and cube the celeriac, which can be a bit awkward but goes faster if you use a sharp knife and don't overthink it. Toss the cubes with 1 tablespoon of olive oil, salt, and pepper, then spread them on a baking tray in a single layer so they have room to caramelize rather than steam.

Roast until golden and tender:

This takes 25 to 30 minutes, and you'll want to turn the pieces halfway through so they develop color on all sides—that's where the magic happens. Your kitchen will smell incredible around minute 20, and that's your signal to start the other components.

Build the base while celeriac roasts:

Heat 1 tablespoon of olive oil in a large pot over medium heat and sauté the chopped onion for about 4 minutes, stirring occasionally, until it turns translucent and soft. Add the minced garlic and diced potato, cooking for another 2 minutes so the garlic releases its fragrance but doesn't brown.

Combine and simmer:

Transfer the roasted celeriac from the tray into the pot with the vegetables, then pour in the vegetable broth and bring everything to a gentle boil. Reduce heat and let it simmer for 15 to 20 minutes until all the vegetables are falling-apart soft, which means the potato should practically dissolve when you poke it.

Toast the hazelnuts for the crumble:

While the soup simmers, add the chopped hazelnuts to a dry skillet over medium heat and toast them for 3 to 4 minutes, shaking the pan occasionally, until they're fragrant and start to darken just slightly. Add the butter and sea salt, stirring constantly for about 30 seconds so every nut gets coated, then remove from heat and let it cool slightly so the hazelnuts stay crisp.

Blend until silky:

Use an immersion blender to purée the soup right in the pot, moving it around so you catch every pocket of vegetables, until the texture is completely smooth and luxurious. If you're using a countertop blender, work in batches so you don't overfill it, and be careful because the soup is hot.

Finish with cream and seasoning:

Stir in the cream if you're using it, then taste the soup and adjust the salt and white pepper to your preference—it should taste balanced, not aggressively seasoned. This is the moment where you become the authority; if it needs brightness, add it now rather than trying to fix it in the bowl.

Serve with crumble and garnish:

Ladle the soup into bowls and top each one generously with the hazelnut crumble so you get that textural contrast in every spoonful. Scatter some fresh parsley on top if you want a hint of herbaceous freshness cutting through the earthiness.

Save to Pinterest

There's something about ladling a bowl of this soup for yourself after a long day that feels like an act of self-care disguised as dinner. The warmth of it, the contrast between the silky soup and that crisp, buttery crumble—it reminds me that sometimes the best meals are the ones you cook without an audience.

Why Celeriac Deserves Your Attention

Celeriac is one of those vegetables that sits in the market looking almost apologetic about its appearance, but once you bring it home and roast it, you understand it was just waiting for the right technique. It's not celery with a root; it's something entirely different—subtle, refined, almost nutty when treated right. Most people skip past it for flashier vegetables, which is their loss because celeriac soup converts even the skeptics.

The Crumble is Non-Negotiable

I've made this soup without the hazelnut topping exactly once, thinking maybe the soup stood well enough on its own, and I was wrong. The crumble isn't just texture; it's a completely different dimension of flavor that transforms the bowl from pleasant to unforgettable. When the warm soup meets that buttery, nutty crunch, something happens that's greater than the sum of its parts.

Variations and Personal Touches

This soup is forgiving enough to adapt to what you have and what you crave, which is part of why I keep making it. I've added fresh thyme when I had it, a small squeeze of lemon juice when the soup needed brightness, and even experimented with different nuts in the crumble. The bones of the recipe are solid, but the personality is entirely yours to create.

• Try almonds or walnuts in the crumble if hazelnuts aren't available, each bringing its own character to the bowl.
• A drizzle of truffle oil over the top transforms this into something restaurant-worthy for a dinner party.
• Make a double batch and freeze half—this soup reheats beautifully and tastes even better the next day.

Save to Pinterest

This soup has become the meal I make when I want to feel like I'm taking care of myself, and it never fails to deliver. There's something honest about it, the way it honors simple ingredients and lets each one shine.

Recipe FAQs

→ Can I make this soup ahead of time?

Absolutely. The base keeps beautifully for 3-4 days refrigerated. Store the hazelnut crumble separately at room temperature and add just before serving to maintain crunch. Reheat gently over medium-low heat, stirring occasionally.

→ What can I substitute for celeriac?

Parsnips or cauliflower work well as alternatives, though the flavor profile will shift. Parsnips add sweetness, while cauliflower creates a milder, lighter soup. Adjust roasting times accordingly as celeriac takes longer to soften.

→ Is this soup freezer-friendly?

Yes, freeze the soup base without cream for up to 3 months. Thaw overnight in the refrigerator, then reheat and stir in cream when warming. The hazelnut crumble is best made fresh, though you can toast and store nuts in an airtight container.

→ How do I achieve the smoothest texture?

Roasting the celeriac first is key—it softens the fibers and deepens flavor. Use an immersion blender directly in the pot, or work in batches with a high-speed countertop blender. For restaurant-smooth results, pass through a fine-mesh sieve after blending.

→ Can I use other nuts?

Walnuts or pecans make excellent substitutes, offering similar earthy richness. Toast them the same way with butter and salt. For a nut-free version, try pumpkin seeds or sunflower seeds for crunch, though the flavor profile will change.

→ What bread pairs well?

A crusty sourdough or country loaf is perfect for dipping. The tangy sourdough balances the earthy sweetness. For something lighter, try warm baguette slices or focaccia with rosemary, which echoes European comfort food traditions.