Antony Worrall Thompson's tasty fish pie made with coley and prawns in a béchamel sauce and creamy potatoes makes an easy midweek supper.

Serves: 4
Cooking time: medium

INGREDIENTS:
* 500ml shop bought béchamel sauce
* 1 tbsp lemon juice
* 450g coley (or other white fish)
* 250g shelled prawns
* 500g potatoes

METHOD:
* Put the fish in a wide pan with enough cold water to half cover the fish; bring to a gentle simmer for four to five minutes and leave to cool in the water.
* Remove any skin and bone from the cooked fish and flake the flesh.
* Heat the béchamel sauce to boiling point and add the lemon juice.
* Fold in the flaked fish and the prawns, heat through and season to taste with salt and pepper.
* Boil the potatoes until done and drain well, then add a knob or two of butter and mash until creamy.
* In a buttered gratin dish, pipe a deep border of hot mashed potatoes around the edge of a serving dish. Put the dish in the oven until the potato browns. Once the potato has browned spoon the fish mixture into the centre and serve.