Butter-seared cod with smoked butter sauce, kohlrabi and horseradish

Niklas Ekstedt’s butter-seared cod recipe is a masterclass in balanced flavours – pan-fried cod loins basted in golden butter, served with two ways with kohlrabi and a luxuriously silky smoked butter sauce. Sharp pickled kohlrabi cuts through richness while warm horseradish-spiked kohlrabi makes this an elegant, memorable dinner party main course.

By Niklas Ekstedt
From Saturday Kitchen 24Oct26

This recipe scores Nutri-Score C – high quality lean protein from cod balances rich butter and cream. Portion sizes are generous; the smoked butter sauce provides wonderful flavour so a little goes a long way. Serve with steamed greens or new potatoes to round out the meal.

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How the timings work

• Make the pickle first – it needs 30 minutes minimum to infuse; can be made up to 3 days ahead and kept in the fridge.
• Prep all vegetables and garnishes before you start cooking – everything moves quickly once the pan goes on heat.
• Cook the kohlrabi garnish next – it takes about 10 minutes and can be kept warm while you fry the fish.
• Make the sauce while the cod rests – it stays warm perfectly for 10–15 minutes without separating.
• Serve immediately – this dish is at its best when everything is freshly cooked and piping hot.

Method

Pickle the kohlrabi (5 mins + 30 mins stand)

1. Make the brine – put 50ml white wine vinegar, 100g caster sugar and 150ml water in a saucepan. Bring to the boil, stirring until sugar dissolves completely. Remove from heat and leave to cool fully.
2. Slice and steep – use a mandoline or sharp knife to cut one kohlrabi paper-thin. Add slices to the cooled liquid. Leave for at least 30 minutes – longer gives sharper flavour.

Warm kohlrabi and horseradish garnish (10 mins)

1. Soften the base – melt 20g butter in a saucepan over medium heat. Add 1 finely chopped shallot and cook gently until soft and translucent.
2. Cook the kohlrabi – add the second kohlrabi, cut into 5mm cubes. Cook for 2 minutes. Pour in 50ml dry cider or white wine and simmer until reduced by half. Add 75ml fish stock and cook until liquid coats the vegetables and kohlrabi is tender with a little bite remaining.
3. Finish with punch – stir in 1 tsp cider vinegar, 1 tbsp chives and 15g freshly grated horseradish. Season lightly with sea salt. Keep warm – do not boil.

Smoked butter sauce (8 mins)

1. Reduce gently – pour 150ml double cream and 1 tsp cider vinegar into a saucepan. Simmer gently over low heat – do not boil hard or it may split.
2. Emulsify with butter – reduce heat to lowest setting. Whisk in 150g cold-smoked butter, a few pieces at a time, until sauce is silky and fully combined. Keep warm – do not let it boil or the sauce will separate.

Butter-sear the cod (10 mins + 2 mins rest)

1. Season and dry – lightly sprinkle 4 cod loins with sea salt. Leave for 15–20 minutes then pat completely dry with kitchen paper – dry surface gives the best sear.
2. High-heat fry – heat 2 tbsp neutral oil in your frying pan over high heat. Place loins in presentation-side down. Fry undisturbed for 3 minutes until deep golden and crisp.
3. Baste with butter – turn heat down slightly. Add 50g butter. As it foams, spoon it continuously over the fish for another 2–3 minutes. Check core temperature with an instant-read thermometer – aim for 42–44°C for tender, perfectly cooked flesh.
4. Rest – remove to a warm plate and leave to rest for 2 minutes. This relaxes the fibres and makes the fish even more tender.

Plate and serve (5 mins)

1. Build the base – spoon a neat mound of warm kohlrabi and horseradish mixture slightly off-centre on each warm plate.
2. Top and drape – place a cod loin on top. Arrange 3 or 4 pickled kohlrabi slices over the fish like fine petals.
3. Sauce and garnish – spoon smoked butter sauce around the plate. Scatter over extra grated horseradish, dill tips, bronze fennel and chives. Drizzle with dill oil. Serve immediately.

Techniques for Success

1. Pat dry and sear hot
   If done wrong – pale soggy surface, fish sticks to pan, uneven cooking.
   Success – deep golden crisp crust, moist flaky centre. Patting dry removes surface moisture so the fish sears rather than steams.
2. Baste slowly, do not boil the sauce
   If done wrong – butter sauce separates, oily grainy texture, greasy mouthfeel.
   Success – glossy creamy emulsion that clings gently to the fish. Add butter off direct heat and keep temperature low; sauce stays stable for 15 minutes.
3. Dual texture kohlrabi
   If done wrong – pickles too sharp or soft; warm kohlrabi mushy or bland.
   Success – crisp bright pickle contrasts sweet tender warm kohlrabi. Balance vinegar with sugar; cook cubes until just tender with a gentle bite.

Tips & Swaps

• Get ahead: Pickled kohlrabi keeps for up to 3 days in a sealed jar in the fridge – flavour improves over time. Prep all garnishes and cube kohlrabi hours in advance; keep covered and chilled.
• Sustainable fish: Use MSC certified cod where possible. Excellent alternatives include coley, pollack, hake or haddock – adjust cooking time by ±1 minute based on thickness.
• Smoked butter hack: If you cannot buy cold-smoked butter, melt 150g unsalted butter and infuse with a pinch of smoked sea salt and ¼ tsp smoked paprika; strain and cool slightly before using.
• Lighter option: Reduce double cream to 100ml and thicken with ½ tsp cornflour mixed with cold water; use half the butter for basting and finish with a squeeze of lemon.
• Flavour balance: Fresh horseradish loses pungency quickly – grate just before serving and taste as you go. Add gradually; you can always add more but cannot take it out.
• Serve with: Buttered new potatoes, steamed asparagus or wild rice to soak up the wonderful sauce. Avoid heavy starches that overpower the delicate fish and elegant flavours.

Wine Pairing

Recommended by Olly Smith:

Mason’s Kloof Stellenrust Barrel Fermented Chenin Blanc, South Africa, 2025 – Asda, £10.32

This beautifully textured Chenin Blanc is the perfect match for this dish – its waxy pear and quince notes mirror the smoked butter sauce while bright citrus acidity cuts through richness and complements the vinegar and horseradish. Barrel fermentation gives gentle oak depth that stands up to the butter basting without overwhelming the delicate cod.

Here are equally good alternatives that pair beautifully with this dish:

• Asda Extra Special Chenin Blanc – Asda, £8.00.
  Crisp, clean and zesty with green apple and white peach; an excellent budget choice that highlights the fish and pickled kohlrabi.
• Sainsbury’s Taste the Difference Loire Valley Sauvignon Blanc – Sainsbury’s, £9.00.
  Silex-styled with flinty mineral notes and fresh gooseberry; the classic pairing for buttered white fish dishes.
• Tesco Finest Condrieu-style Viognier – Tesco, £11.00.
  Ripe stone fruit with subtle floral depth; richer texture that complements the smoked butter sauce beautifully.

* Prices checked October 2026 and may vary. The alternatives are our suggestions, not necessarily wines recommended by Olly Smith.

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