Swordfish Steak Recipe: Posh Fish and Chips with Mushy Peas

It was Sunday, and Sunday called for posh fish and chips. This swordfish steak recipe is my version: a thin steak griddled hot and fast, olive oil confit chips finished on the plancha, and mushy peas turned into a purée with capers and a spoonful of my own fermented salsa verde. In Spain, ask for rodaja de emperador at the fish counter (pez espada is the literal name).

Swordfish is a firm, meaty fish with pale flesh and a moderate oil content, which is why it stands up to a very hot griddle. It still turns dry in no time, so a half-inch steak gets about four minutes in total and not a second more.

The chips were gorgeous, trust me. The photo was taken with them still crisping on the plancha, because the football was about to start.

Swordfish Steak Recipe Ingredients (Serves One)

For the griddled swordfish:

• 250 g swordfish steak (rodaja de emperador), about half an inch thick, defrosted overnight in the fridge
• Olive oil, for brushing
• Sea salt and black pepper

For the olive oil confit chips:

• 250 g potatoes, cut into chips 1.5-2 cm thick
• 1 tbsp water, for the microwave
• Olive oil, about 1 cm deep in a small pan
• 1-2 tsp ghee, for the plancha
• Salt

For the mushy peas purée:

• 100 g frozen peas
• 1 tbsp water, for the microwave
• 1 garlic clove
• Several mint leaves
• 1 tbsp fermented salsa verde (see the note below)
• 1 heaped tsp capers, drained
• Olive oil, drizzled in until smooth

How to Cook the Swordfish with Chips and Mushy Peas

Start with the confit chips, because they take longest. Make the purée while they confit, and cook the fish last so it goes straight from the pan to the plate.

Confit chips

1. Rinse the chips briefly to remove surface starch. Microwave them with 1 tbsp water, covered, for 2-3 minutes until just softening. Drain and steam-dry for 1 minute. This jump-starts the cooking so the confit stage is shorter and more even.
2. Heat the olive oil to 115-125°C, about 1 cm deep in a small pan, enough to half-submerge the chips. Add the chips in a single layer to keep the temperature steady. Cook for 15-20 minutes, turning once, until pale, flexible and fully tender. Low-temperature oil gives a creamy middle without a harsh crust.
3. Lift the chips out, drain and cool for 5 minutes so the surface dries. Strain the oil and keep it to use again.
4. Heat the plancha on maximum and add the ghee. Add the chips and press lightly for maximum contact. Brown deeply, flip, and finish until crisp and golden, 3-5 minutes. Ghee browns cleanly at high heat without burning. Salt immediately so it sticks.

Mushy peas purée

1. Microwave the frozen peas with 1 tbsp water, covered, for 2 minutes. Microwaving keeps their sweetness and colour better than boiling.
2. Blend the peas with the garlic, mint, salsa verde and capers, drizzling in olive oil until smooth and spoonable.

Swordfish

1. Pat the steak dry so the surface sears instead of steaming. Brush lightly with olive oil and season with sea salt and black pepper.
2. Heat a griddle pan until smoking hot, about 2 minutes.
3. Cook the swordfish for 2-3 minutes on the first side for a defined sear. Flip and cook 1-2 minutes more. For a half-inch steak that is about 4 minutes in total, until just opaque all the way through.
4. Rest for 2 minutes, then serve with the purée and the chips.

A Note on the Fermented Salsa Verde

I used my own because that is what I had: green chillies, garlic, carrot and black peppercorns, fermented for about three weeks (19 February to 14 March). A good shop-bought salsa verde will work as a stand-in, but it is usually milder and more herby, so the purée will have less heat and tang.

If you can get rodaja de emperador, this swordfish steak recipe is quick enough for an occasional weeknight too, with the chips as the only real wait.

A Note on Mercury

Swordfish can contain high levels of mercury because it is a large, long-lived predatory fish. UK guidance says pregnant women and those trying to conceive should avoid it, and children under 16 should not eat it. Other adults are advised to have no more than one portion a week (NHS guidance).

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This swordfish steak recipe is featured in my Fish & Seafood Hub, a collection of my fish and seafood recipes.

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Wonky photos, proper food, genuine adventures — The Flexible Chef