Cook Well for Less

Simple Fish Pie

A creamy white-fish and pea filling under fluffy mash, with enough cooked filling reserved for crispy fishcakes.

Prep
20 mins
Cook
50 mins
Total
70 mins
Difficulty
easy
Serves
2
Illustration: Golden mashed-potato fish pie with white fish and peas visible through an open corner
Cook Well for Less · AI-generated pencil and watercolour illustration

Get ready

Ingredients for 2 portions

  • 1 × approximately 500–520 g pack frozen white fish filletsdefrosted in the fridge, patted dry and cut into large chunks
  • 600g white potatoespeeled and cut into even pieces
  • 1 medium onionfinely chopped
  • 150g frozen peas
  • 20 g for the mash and 40 g for the sauce
  • 50 ml for the mash and 450 ml for the sauce

Optional extras

  • 40 g mature Cheddargrated
Equipment
  • two saucepans
  • colander
  • wooden spoon
  • potato masher
  • appropriately sized ovenproof dish
  • shallow container for the reserved filling

Cook

Method

  1. Make the mash

    Put the potatoes in a saucepan, cover with cold water and bring to the boil. Simmer for 15–20 minutes until completely tender, then drain well and leave them to steam for a minute or two. Mash with the butter and milk measured for the mash, without overworking them.

    New to this?How to make good mashed potato

  2. Soften the onion

    While the potatoes cook, melt the butter measured for the sauce in a large saucepan over a medium-low heat. Add the onion and cook gently for about 8 minutes, stirring occasionally, until soft.

    New to this?How to soften an onion

  3. Make the sauce

    Stir the flour into the onion and butter and cook for 1 minute. Add the milk measured for the sauce a little at a time, stirring well after each addition. Bring to a gentle simmer and cook for 3–4 minutes, stirring, until smooth and thick enough to coat the spoon.

  4. Cook the fish filling

    Add the defrosted fish chunks and simmer gently for 5–7 minutes, stirring carefully, until the fish is opaque, flakes easily and is steaming hot throughout. Stir in the frozen peas for the final 3 minutes. Add black pepper, but taste before adding any extra salt.

  5. Reserve the fishcake filling

    Spoon roughly two-fifths of the fully cooked fish filling — a little less than half — into a shallow container for Crispy Fishcakes. If you have kitchen scales, put the container on them and aim for approximately 450 g as you spoon, rather than trying to weigh the hot saucepan. Cover, cool and get it into the fridge within 2 hours. Use within 48 hours or freeze it once cool.

  6. Assemble the pie

    Heat the oven to 200°C / 180°C fan / Gas 6. Spoon the remaining fish filling into an appropriately sized ovenproof dish. Spread the mash over the top and rough it up with a fork. Add the Cheddar if using.

  7. Bake

    Bake for 20–25 minutes, until the top is golden and the filling is bubbling and steaming hot throughout. Leave to stand for 5 minutes before serving.

Make it stretch

Fish pie tonight, crispy fishcakes next

Make one generous batch of creamy fish filling and reserve roughly two-fifths — approximately 450 g — after the fish is fully cooked.

The remaining filling still makes a substantial two-portion fish pie; the reserved portion combines with potato to make six fishcakes for another two-portion dinner.

See how Make It Stretch works

How to store what you save

  1. Illustration: Six crisp fishcakes with peas, one split to show its fish filling

    Next meal

    Crispy Fishcakes

    Mix the reserved cooked fish filling with fluffy potato, shape six cakes, coat them with flour, egg and breadcrumbs, then fry until crisp and steaming hot.

    Cook Crispy Fishcakes

Use what you've got

Easy swaps

  • Frozen white fish filletsFrozen basa, pollock or another uncoated white fish can be used; follow the pack instructions and check the current allergen label.

For later

Storing and using leftovers

Storage

Cool any fish pie or filling that will not be eaten straight away, put it into the fridge within 2 hours and use within 48 hours.

Freezing

Freeze the reserved cooked filling if you will not use it within 48 hours. Defrost it fully in the fridge, then use it for the fishcakes and heat until steaming hot throughout. Only reheat once.

Practical guide:How to freeze leftovers safely

Ideas

Combine the deliberately reserved fish filling with freshly cooked potato, then coat and fry it as Crispy Fishcakes.

Community

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