Name: Rosti-Topped Fish Pie Recipe
Prep time: 15 min
Cook time: 20 min
Total time: 35 min
Cuisine: British
Ingredients: 300g waxy potatoes, halved; 250g skinless coley fillets (frozen coley is suitable); 300ml milk; 50g butter, divided; 1 leek, finely sliced; 25g flour; 2 tbsp chopped parsley; 2 tsp Dijon mustard

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Introduction

This Rosti-topped fish pie is a comforting and flavorful twist on a classic favorite. Tender coley fish in a creamy leek sauce is beautifully topped with crispy, golden rösti potatoes for a satisfying meal the whole family will enjoy.

A white rectangular baking dish holds a layered casserole with a top layer of golden-brown shredded potatoes, some edges slightly crisp and darkened, showing texture from the thin strands. Below the potato layer, you can see a creamy white sauce mixed with pieces of chicken and green vegetable bits, likely leek or celery, giving a soft, tender look inside. The dish is placed on a white marbled surface with a shiny metal spoon and a fork next to it, reflecting light subtly. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

300g waxy potatoes, halved
250g skinless coley fillets (fresh or frozen)
300ml milk
50g butter
1 leek, finely sliced
25g flour
2 tbsp chopped parsley
2 tsp Dijon mustard

Instructions

Step 1: Cook the potatoes in boiling salted water for 5–7 minutes until almost tender but still firm enough to grate. Drain them and refresh under cold running water.
Step 2: Place the coley fillets in a shallow saucepan and pour over the milk. Bring to a simmer and cook gently for 5 minutes. Drain the fish, reserving the milk, and set the fish aside.
Step 3: Heat half the butter in a medium saucepan and add the sliced leek. Cook gently for 5–6 minutes until softened.
Step 4: Stir in the flour and cook for 1 minute without browning. Remove the pan from the heat and gradually whisk in the reserved milk, stirring well to avoid lumps.
Step 5: Return the pan to the heat and stir until the sauce comes to a boil. Let it simmer gently for 2 minutes, then stir in the chopped parsley and Dijon mustard.
Step 6: Preheat the grill to high. Flake the cooked fish into large chunks and fold gently into the sauce. Transfer this mixture to a small ovenproof dish.
Step 7: Coarsely grate the cooked potatoes. Melt the remaining butter, toss with the grated potatoes, season with salt and pepper, then scatter evenly over the fish mixture.
Step 8: Place the dish under the grill for 5–10 minutes until the rösti topping is golden and crispy, and the potatoes are tender.

Tips & Variations

Use waxy potatoes to ensure the rösti topping holds together well and crisps up nicely.
Substitute coley with other white fish such as cod or haddock if preferred.
Add a pinch of nutmeg to the sauce for extra warmth and depth of flavor.
For a richer sauce, stir in a tablespoon of crème fraîche before adding the parsley and mustard.

Storage

Store any leftover fish pie in an airtight container in the refrigerator for up to 2 days. Reheat gently in the oven at 160°C (320°F) until warmed through to keep the topping crisp. Avoid microwaving to prevent the rösti from becoming soggy.

How to Serve

A small white square baking dish filled with a baked casserole, where the top layer is golden brown shredded potato that looks crispy and uneven, with some darker brown spots around the edges. Beneath this layer, you can see a creamy mixture with chunks of white chicken meat and bits of green herbs or vegetables peeking through. The dish is placed on a white marbled surface, and beside it are a silver spoon and fork resting on a white textured mat. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use fresh fish instead of frozen coley?

Yes, fresh coley or any firm white fish works well. Adjust cooking time slightly if the fish fillets are thicker to ensure they are cooked through.

How do I know when the rösti topping is done?

The rösti is ready when it turns golden brown and crispy on top, and the potatoes underneath are tender. This usually takes about 5 to 10 minutes under a medium-high grill.