25 g (1 oz) watercress, roughly chopped (optional)
390 g (12¾ oz) shop-bought fish pie mixture (available from the chilled section of supermarkets), or use bite-sized chunks of salmon, white fish fillet and smoked haddock
200 g (7 oz) raw peeled king prawns
3 tablespoons crème fraîche
75 g (3 oz) Cheddar cheese, grated
green salad, to serve
salt and pepper
Cook the potatoes in a pan of lightly salted boiling water for 10–12 minutes, until tender.
Hard-boil the eggs, if using, in a pan of simmering water for about 8 minutes. Drain and hold under cold running water. Once cool enough to handle, remove the shells and cut the eggs into wedges.
Place the milk, flour and half the butter in a saucepan and bring slowly to the boil, stirring constantly with a balloon whisk, until thick and smooth. Simmer for 1–2 minutes, then season lightly and take off the heat.
Stir the parsley, watercress (if using), fish, prawns and egg into the sauce, then transfer to an ovenproof dish.
Drain the potatoes and mash them with the crème fraîche and the remaining butter. Season to taste, then spoon over the fish mixture and scatter with the grated cheese. Place the pie in a preheated oven, 220˚C (425˚F), Gas Mark 7, for 12–15 minutes, until golden and bubbling and the fish is cooked. Serve with green salad.