Mary Berry’s Fish Pie with Cheesy Mash Recipe

This Mary Berry inspired fish pie is the kind of comforting supper I come back to again and again: tender flakes of fish and sweet prawns in a silky, lemony white sauce, topped with a deeply savoury cheesy mash. The mash goes golden and crisp at the edges, while the filling stays creamy and rich underneath. It is very doable for a confident beginner, just take it step by step. Set aside about 1 hour to 1 hour 10 minutes from start to serving, including a short rest.

Ingredients

For the fish and creamy sauce

600ml whole milk
1 bay leaf
600g mixed fish fillets (skinless and boneless), such as cod, smoked haddock and salmon
200g raw king prawns, peeled
40g unsalted butter
1 small onion, finely chopped
1 leek, trimmed and finely sliced (wash well)
40g plain flour
2 tbsp double cream (optional, for richness)
1 tsp Dijon mustard
Finely grated zest of 1 lemon
1 tbsp lemon juice
2 tbsp chopped fresh parsley
100g frozen peas
Salt and freshly ground black pepper

For the cheesy mash topping

1kg floury potatoes (Maris Piper or King Edward), peeled and cut into chunks
75g unsalted butter
100ml warm milk (or use some reserved fish-poaching milk)
100g mature cheddar, grated
25g Parmesan, finely grated
Pinch of nutmeg (optional)
Salt and freshly ground black pepper

To assemble

A little butter, for greasing the baking dish

How to Make Mary Berry’s Fish Pie with Cheesy Mash

Prepare the oven: Preheat the oven to 200°C or 180°C fan. Place a shelf in the middle of the oven so the pie cooks evenly and the topping colours nicely.
Grease the dish: Lightly butter a medium baking dish (about 2 litres). Set aside so it is ready as soon as the filling is finished.
Cook the potatoes: Put the potatoes into a large pan of cold, salted water. Bring to the boil, then simmer for 15 to 20 minutes until completely tender. Drain well, then return to the hot pan for 2 minutes to steam-dry.
Poach the fish: Pour the milk into a wide saucepan and add the bay leaf. Warm until just steaming. Add the fish fillets and poach gently for 4 to 5 minutes, turning once, until the fish is only just starting to flake. Lift the fish out onto a plate. Strain the poaching milk into a jug and keep it nearby.
Start the sauce: In the same saucepan, melt the butter over a medium heat. Add the onion and leek and cook for 8 to 10 minutes, stirring, until soft but not browned.
Thicken the sauce: Stir the flour into the leeks and onions and cook for 1 minute. Gradually whisk in the reserved poaching milk, a little at a time, until smooth. Simmer for 3 to 5 minutes, stirring, until thick enough to coat the back of a spoon.
Finish the filling: Stir in the cream (if using), Dijon mustard, lemon zest, lemon juice, parsley and peas. Season with salt and pepper. Break the fish into large chunks and gently fold it into the sauce with the prawns.
Assemble: Spoon the fish filling into the greased dish and level the top. If it looks very loose, let it stand for 5 minutes so it thickens slightly before topping.
Make the cheesy mash: Mash the potatoes with the butter. Add the warm milk gradually until creamy (you may not need every last drop). Stir in the cheddar, Parmesan and nutmeg, then season to taste.
Top the pie: Spoon the mash over the filling and spread gently to the edges to seal. Rough up the surface with a fork so it crisps beautifully.
Bake: Bake for 25 to 30 minutes, or until bubbling around the edges and golden on top. If you want extra colour, pop it under the grill for 1 to 2 minutes, keeping a close eye on it.
Cool and serve: Rest the pie for 10 minutes before serving. This helps the filling settle, so you get neat, creamy portions rather than a runny puddle on the plate.

Tips

Why is my fish pie watery?

Watery fish pie usually comes from an under-thickened sauce or potatoes that were not steam-dried. Simmer the sauce until it properly coats the back of a spoon, and always let the drained potatoes sit in the hot pan for a minute or two before mashing.

How do I stop the mash sinking into the filling?

Make sure the sauce is thick and not boiling hot when you top it. A quick 5 minute stand before adding the mash makes a big difference. Also, spread the mash gently rather than pressing it down.

How can I avoid overcooked, dry fish?

Poach the fish only until it is just starting to flake, then finish cooking it in the oven. Keeping the poaching gentle (steaming, not boiling) helps the fish stay tender.

Can I make this ahead without it losing quality?

Yes. Assemble the pie, cool, cover and refrigerate for up to 24 hours. Bake from chilled, adding 10 to 15 minutes, and make sure it is piping hot all the way through.

Serving Suggestions

Steamed green beans or tenderstem broccoli with a knob of butter
Buttered spinach with a squeeze of lemon
A crisp green salad with a sharp vinaigrette
Crusty bread to mop up the creamy sauce

Storage

Room temperature

Let the pie cool for no more than 1 to 2 hours, then refrigerate. Because this is a fish and dairy based dish, it should not be left out for long.

Refrigerator

Store covered in the fridge for up to 2 days. Reheat in the oven at 180°C (160°C fan) for 20 to 30 minutes, or until piping hot in the centre. Cover with foil if the top is getting too brown.

Freezing

Freeze in an airtight container for up to 2 months. Thaw overnight in the fridge, then bake at 180°C (160°C fan) until hot throughout. For best texture, freeze after assembling but before baking, then bake from thawed.

Nutrition

Calories: 560 kcal
Carbohydrates: 45 g
Protein: 38 g
Fat: 26 g
Saturated Fat: 14 g
Sodium: 620 mg

Nutrition values are estimates and will vary depending on the fish you use and exact portion sizes.

FAQs

Can I use frozen fish for fish pie?

Yes. Thaw it fully in the fridge first, then pat it dry with kitchen paper before poaching or folding into the sauce. This prevents excess water from thinning the filling.

What fish is best in Mary Berry’s fish pie?

A mix gives the best flavour and texture. I like cod (or haddock) for chunky flakes, salmon for richness, and a little smoked haddock for depth. You can adjust the mix to what is fresh and available.

Can I make fish pie without prawns?

Absolutely. Leave the prawns out and increase the fish by about 150–200g, or add extra peas and a handful of spinach for a lighter filling.

How do I fix a lumpy white sauce?

Take the pan off the heat and whisk vigorously. If it is still lumpy, pass it through a sieve back into the pan, then continue simmering until thick. Adding the milk gradually helps prevent lumps in the first place.

Can I assemble fish pie in advance and bake later?

Yes. Assemble, cool, cover and refrigerate for up to 24 hours. Bake from chilled and add extra time so the centre gets properly hot.