Creamy Fish Pie

I made this on a rainy Tuesday after finding smoked haddock on sale, and the kitchen filled with that warm, milky steam that makes everything feel safe. The fish flaked apart so easily I worried I'd overcooked it, but it turned out perfect. My neighbor knocked just as I was forking the potato topping, and I ended up serving her a portion straight from the dish.

The first time I served this to friends, I panicked because the sauce looked too thin, but it thickened perfectly in the oven. One friend scraped her plate clean and asked if I'd learned to cook in England. I hadn't, but I took it as the highest compliment and made it again the following week.

Ingredients

• White fish fillets (400 g, such as cod or haddock): Choose thick, firm fillets that won't fall apart during poaching, and make sure they're skinless and boneless to save yourself the hassle later.
• Smoked fish fillets (200 g, such as smoked haddock): This is where the magic happens, the smokiness seeps into the milk and gives the whole pie a subtle richness that plain fish just can't deliver.
• Cooked, peeled prawns (150 g, optional): I like adding these for a bit of sweetness and texture, but the pie is just as lovely without them if you want to keep it simple.
• Whole milk (400 ml for poaching, 60 ml for mash): Full-fat milk is essential here, it creates a creamy sauce and silky mashed potatoes without needing cream.
• Bay leaf and small onion (halved): These infuse the poaching milk with a gentle savory note, just remember to fish them out before making the sauce.
• Unsalted butter (2 tbsp for sauce, 40 g for mash): Butter makes the roux smooth and the mashed potatoes fluffy, don't skimp or use margarine.
• Plain flour (2 tbsp): This thickens the sauce into a luscious coating for the fish, stir it constantly so you don't get lumps.
• Frozen peas (75 g): They add a pop of color and a hint of sweetness, no need to thaw them first.
• Fresh parsley (2 tbsp, chopped): A handful of parsley brightens the whole dish and makes it taste fresher, dried parsley won't give you the same lift.
• Dijon mustard (1 tsp): Just a touch adds a subtle tang that balances the creaminess without making it taste mustardy.
• Floury potatoes (900 g, such as Maris Piper): These mash up light and fluffy, waxy potatoes will turn gluey so choose the right variety.
• Salt, black pepper, and white pepper: Season each layer as you go, the mash benefits from white pepper which is milder and won't speckle the topping.

Instructions

Preheat and Prepare:

Set your oven to 200°C (180°C fan) or 400°F so it's ready when you need it. This gives you time to get everything else done without waiting later.

Poach the Fish:

Place the white and smoked fish in a large pan with the milk, bay leaf, and halved onion, then bring it to a gentle simmer over medium heat. Let it poach for 6 to 8 minutes until the fish is just cooked through and flakes easily, then lift it out with a slotted spoon and set aside, keeping the poaching milk for the sauce.

Boil the Potatoes:

While the fish poaches, put the peeled and chopped potatoes in a pot of salted water and boil for 15 to 20 minutes until they're tender when pierced with a fork. Drain them well, then mash with the 60 ml of milk and 40 g of butter until smooth and creamy, seasoning with salt and white pepper.

Make the Sauce:

In a clean saucepan, melt the 2 tbsp of butter over medium heat, stir in the flour, and cook for about a minute to form a roux. Gradually whisk in the reserved poaching milk, stirring constantly until the sauce thickens and becomes smooth and glossy.

Finish the Filling:

Stir the mustard, peas, and chopped parsley into the sauce, then season with salt and pepper to taste. Gently fold in the poached fish, breaking it into large chunks, and add the prawns if you're using them.

Assemble the Pie:

Spoon the fish mixture into a baking dish and spread it evenly, then top with the mashed potatoes, using a fork to fluff up the surface so it crisps nicely. The peaks and ridges will turn golden in the oven.

Bake Until Golden:

Slide the dish into the preheated oven and bake for 25 to 30 minutes until the topping is golden brown and the filling is bubbling around the edges. Let it rest for 5 minutes before serving so the sauce settles and doesn't spill everywhere when you scoop it out.

Save

My mum used to make this on Fridays, and the smell of smoked fish and butter would drift through the house and settle into the curtains. Now when I make it, I'm back at her table, scraping up the last bits of creamy sauce with a piece of bread.

Variations and Swaps

If you can't find smoked haddock, smoked mackerel works beautifully and brings a richer, almost buttery flavor. You can swap the prawns for chunks of cooked salmon, or leave them out entirely if you want to keep it simple and budget-friendly. For a bit of indulgence, stir a handful of grated mature cheddar into the mashed potato topping before spreading it over the fish, it melts into golden, savory pockets.

Serving Suggestions

I love serving this with steamed green beans or tenderstem broccoli on the side, something green and crisp to cut through the richness. A simple salad with a sharp vinaigrette works too, especially if you're serving it in warmer weather. Honestly, though, it's hearty enough to stand on its own with just a bit of crusty bread to mop up the sauce.

Storage and Reheating

Leftovers keep well in the fridge for up to two days, covered tightly with foil or in an airtight container. Reheat individual portions in the microwave or the whole dish in a low oven, around 160°C, until warmed through and the top crisps up again. I've found that the flavors deepen overnight, so don't be surprised if it tastes even better the next day.

• Let the pie cool completely before covering it, or condensation will make the topping soggy.
• You can freeze it before baking, just assemble, cover well, and bake from frozen, adding an extra 15 to 20 minutes.
• If reheating in the oven, a quick flash under the grill at the end will restore the golden crust.

Save

This pie has a way of turning a regular Wednesday into something worth sitting down for. I hope it brings you the same kind of comfort it's brought me, one forkful at a time.

Common Recipe Questions

→ What types of fish work best in this dish?

White fish like cod and haddock are ideal for their mild flavor and flaky texture, complemented by smoked fish for depth.

→ Can I add seafood other than fish?

Yes, cooked peeled prawns can be folded in to add a subtle sweet seafood note, or salmon can be used as an alternative.

→ How do I achieve a creamy sauce without lumps?

Carefully whisk the flour and butter roux while gradually adding the reserved poaching milk to ensure a smooth, thick sauce.

→ What’s the best way to get a golden mashed potato topping?

Fluff the mashed potatoes with a fork before baking and optionally sprinkle grated mature cheddar for added color and flavor.

→ Are there suggested side dishes to serve with this meal?

Steamed green beans or a crisp, fresh salad pair beautifully to balance the rich, creamy filling.

→ Can this dish be prepared ahead of time?

Yes, you can assemble it in advance and bake when ready, allowing the flavors to meld together nicely.