Sean Ós Fish Pie
A delightful take on a classic fish pie, featuring a creamy white sauce infused with dill and lemon, layered with flaky white fish and topped with a golden, cheesy mashed potato crust. 'Sean Ós' translates to 'Old Style' in Irish, suggesting a traditional yet refined preparation.

🧂 Ingredients
- 700 g Cod or Haddock fillets(skinless and boneless, cut into chunks)
- 50 g Butter
- 50 g All-purpose flour
- 600 ml Milk(warmed)
- 2 tbsp Fresh dill(chopped)
- 1 tsp Lemon zest
- to taste Salt
- to taste White pepper
- 1 kg Potatoes(for mashing)
- 50 g Butter(for mash)
- 100 ml Milk(for mash, or as needed)
- 100 g Mature cheddar cheese(grated, for topping)
- for garnish Fresh parsley(chopped)
👨🍳 Instructions
- 1
Preheat your oven to 200°C (400°F).
💡 Tip: Ensures the pie cooks evenly and the topping browns nicely. - 2
Place the fish chunks in an ovenproof dish. Season lightly with salt and white pepper.
- 3
Make the white sauce: Melt 50g butter in a saucepan over medium heat. Whisk in the flour and cook for 1-2 minutes to form a roux, stirring constantly.
⏱️ 2 minutes💡 Tip: Cooking the roux for a minute or two removes the raw flour taste. - 4
Gradually whisk in the warmed milk until the sauce is smooth and thickened. Bring to a gentle simmer.
⏱️ 5 minutes - 5
Stir in the chopped dill, lemon zest, salt, and white pepper. Taste and adjust seasoning.
💡 Tip: Fresh dill and lemon are key to the bright flavor of this pie. - 6
Pour the sauce over the fish in the ovenproof dish, ensuring the fish is mostly covered.
- 7
Prepare the mashed potato topping: Boil the potatoes until tender. Drain well and mash with 50g butter and about 100ml milk until smooth and creamy. Season with salt and pepper.
⏱️ 20-25 minutes💡 Tip: Ensure the potatoes are well-drained to avoid a watery mash. - 8
Spoon the mashed potato evenly over the fish and sauce. Use a fork to create a decorative pattern on the surface.
💡 Tip: Creating ridges helps the topping crisp up. - 9
Sprinkle the grated cheddar cheese over the mashed potato topping.
- 10
Bake in the preheated oven for 30-35 minutes, or until the topping is golden brown and the filling is bubbling.
⏱️ 30-35 minutes - 11
Let the pie stand for a few minutes before serving. Garnish with fresh chopped parsley.
💡 Pro Tips
- ✓Use a mix of fish for added complexity, such as salmon or smoked haddock.
- ✓For a lighter topping, you can use a mix of mashed potato and cauliflower.
- ✓Ensure the sauce is thick enough to coat the fish; if too thin, simmer it for a few extra minutes.
🔄 Variations
- Add a splash of dry white wine to the sauce for extra flavor.
- Incorporate a tablespoon of capers into the sauce for a briny note.