Equipment
Ingredients
Cheesy Mashed Potato Topping
- 1000 g floury potatoes, peeled and cut into 3cm cubes
- 50 g unsalted butter, cubed
- 50 ml whole milk, warmed
- 100 g mature cheddar cheese, grated
Seafood Filling
- 300 g firm white fish fillet, skinless, pin-bones removed
- 300 g smoked haddock fillet, undyed, skinless, pin-bones removed
- 300 g salmon fillet, skinless, pin-bones removed
- 150 g raw peeled prawns, deveined
Leek and Dill Cream Sauce
- 50 g unsalted butter
- 150 g leek, washed thoroughly and finely sliced
- 50 g all-purpose flour
- 600 ml whole milk, cold
- 10 g dijon mustard
- 10 g fresh dill, finely chopped
- 1 lemon
Nutrition (per serving)
Method
Preheat your oven to 200°C/400°F.
Place the cubed potatoes in a large saucepan, cover with cold salted water, and bring to a boil over medium-high heat. Cook until thoroughly tender.
Drain the potatoes completely in a colander and leave them to steam dry for two minutes.
Return the potatoes to the pan and mash until smooth. Add the cubed butter, warm milk, and half of the grated cheddar cheese, stirring to combine. Set aside.
Cut the white fish, smoked haddock, and salmon into large, 3cm chunks. Wash hands thoroughly with warm water and soap after handling the raw seafood to prevent cross-contamination.
In a medium saucepan, melt the 50g of butter for the sauce over medium heat. Add the sliced leeks and gently sweat until soft and sweet, but not colored.
Stir the all-purpose flour into the leeks to create a roux. Cook this paste for two minutes to cook out the raw flour flavor.
Gradually whisk the cold milk into the leek and flour mixture, adding a small splash at a time and whisking vigorously to prevent lumps.
Bring the sauce to a gentle simmer, whisking continuously, until it becomes thick and velvety. Remove from the heat and stir in the dijon mustard, chopped dill, lemon zest, and lemon juice.
Scatter the raw fish chunks and raw peeled prawns evenly across the base of the 2-liter baking dish. Season lightly with black pepper.
Pour the hot cream sauce directly over the raw fish and prawns, gently shaking the dish to ensure the sauce fills all the gaps.
Spoon the mashed potato evenly over the top of the sauce and filling. Spread it to the edges of the dish to create a seal, preventing the sauce from bubbling over.
Score the surface of the mashed potato generously with a fork to create ridges, then scatter the remaining cheddar cheese over the top.
Bake in the preheated oven for 30 to 35 minutes until the sauce is bubbling up the sides, the fish reaches a safe internal temperature of 74°C/165°F, and the potato crust is deeply golden brown.
Remove the pie from the oven and let it rest for 10 minutes before serving. This allows the incredibly hot sauce to cool slightly and thicken, making it easier to serve.
Chef's Notes
- Using raw fish instead of precooked fish is crucial. Poaching the fish beforehand often results in overcooked, tough proteins once baked. The residual heat of the sauce combined with the oven time cooks the raw fish perfectly.
- Undyed smoked haddock provides the signature smoky depth that defines a traditional British fish pie. If you can only find dyed yellow haddock, it works, but undyed offers a cleaner flavor profile.
- Always wash your hands, cutting boards, and knives thoroughly with hot soapy water after prepping the raw fish to maintain strict kitchen hygiene and avoid cross-contamination.
- Scoring the potato topping with a fork isn't just aesthetic; the ridges catch the oven heat and crisp up beautifully, adding textural contrast to the soft filling beneath.
Storage
Refrigerator: 3 days — Store well covered or in an airtight container once completely cooled.
Freezer: 2 months — Freeze unbaked or fully baked. Defrost completely in the refrigerator for 24 hours before baking or reheating.
Reheating: Reheat portions in the oven at 180C/350F for 20 minutes until piping hot throughout, or microwave until steaming.
