028 / 75 · Fish Without Fuss

Trout with Lemon Leeks and Potatoes

2 plates, each with 1 trout fillet, half the lemon leeks and half the potatoes · Active 25 min · Total 55 min

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Leeks need washing between their layers before they need cooking. Once clean, they soften gently under a little butter and water, making a bed for trout to steam in the covered pan. Potatoes cook in a separate saucepan at the same time. This approach leaves the fish pale and tender rather than promising a crisp surface from a moist, covered method.

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Original hand-drawn illustration of trout with lemon leeks and potatoes.

Wash after opening the layers

Trim away the root and tough dark-green ends, keeping the white and pale-green parts. Split the leek lengthwise so you can see the spaces where grit hides, rinse those layers under drinking water and then slice. A quick rinse of an intact stalk cannot reliably reach the inside. Drain the slices before the butter stage. Use moderate heat and stir regularly; the goal is soft, sweet-smelling leek, not scorched brown strands. A small measured water addition helps the thicker pieces finish without needing more fat.

Make a gentle fish bed

Spread the softened leeks evenly and lay the trout fillets on top, rather than burying them under a dense heap. Cover and keep the liquid gently simmering. The lid traps enough steam to cook the fish without a large bath of sauce. Fillets vary in thickness, so check the thickest section for 145°F/63°C and remove a thinner piece sooner if it is ready. A broad spatula helps lift it without tearing. Keep the potato chunks similar in size and test the center of a larger one with a knife. Lemon goes into the cooked leeks at the end so its flavor remains clear. Share the cooking juices between the plates rather than leaving one portion dry and pouring all the butter over the other.

Ingredients

  • 2 boneless skinless farmed rainbow trout fillets (300 g total raw)
  • 2 medium leeks, white and pale-green parts only, split, washed and sliced (250 g prepared)
  • 2 medium potatoes, scrubbed and cut in 3 cm/1 1/4-inch chunks (400 g raw, skin on)
  • 4 cups drinking water (1 litre), for boiling and draining potatoes
  • 2 teaspoons unsalted butter (10 g)
  • 1 teaspoon olive oil (5 ml/about 4.5 g)
  • 1/4 cup drinking water (60 ml), plus up to 30 ml if the leek pan dries
  • 1 tablespoon plus 1 teaspoon lemon juice (20 ml/about 20 g)
  • 1/4 teaspoon fine salt (1.5 g), divided
  • 1/8 teaspoon black pepper (0.3 g)

Set out

28 cm/11-inch skillet with lid, 2-litre/2-quart saucepan, Sieve, Broad fish spatula, Knife and separate raw-fish board, Kitchen scale, Food thermometer, 2 plates

Allergens

Fish, Milk in butter. Check labels and substitutions.

Make it

  1. Put potatoes and their water in the saucepan. Bring to a boil and simmer for 15–20 minutes until tender through the largest chunks, then drain and cover off the heat.
  2. Meanwhile split and wash the leek layers thoroughly, then slice. Melt butter with oil in the skillet over medium-low heat. Add leeks and half the salt and cook gently for 7–8 minutes, stirring. Add 60 ml water, cover and cook for another 5 minutes until soft.
  3. Keep raw trout cold until needed and use a separate board, cleaning equipment and hands afterward. Lay fillets on the softened leeks and season with remaining salt and pepper. Cover and cook over low heat for about 8–12 minutes, depending on thickness, until the thickest parts reach 145°F/63°C and the flesh is opaque and separates easily. Add a little extra water if the pan dries before fish is ready.
  4. Lift one fillet to each plate with the broad spatula. Stir lemon into the leeks and divide leeks, juices and potatoes between the plates. Serve promptly.

A useful kitchen skill

Open leek layers before washing so grit can escape, and match a covered-pan cooking method with an honestly pale finished fish.

A useful detail

The 55-minute total includes careful leek washing; potatoes cook while the leeks and fish finish. This covered method produces steamed trout, not a browned or crisp-skinned fillet.

Another way

  • Use 300 g raw cod fillets instead of trout, allowing for their thickness and checking 145°F/63°C; recalculate for cod.
  • Replace half the leeks with 125 g thinly sliced onion, cooking until fully soft; the estimate changes.

Keep it well

Refrigerate leftovers promptly in shallow containers at 40°F/4°C or below within 2 hours, or 1 hour above 90°F/32°C. Use within 2 days. Reheat only the needed portion to 165°F/74°C throughout, gently covered with a little drinking water if needed. Fish will firm further during reheating.