All-in-one potato, spinach and caper fish pie

1 Bring the potatoes and 4 eggs to the boil in 2 separate pans of cold water, reduce to a fast simmer once boiling, then cook for 8 min. Drain the potatoes and set them aside. Put the eggs in a colander and cool under cold running water, then peel, chop coarsely and set aside.

2 Heat the oven to 220°C/fan 200°C/gas 7. Heat the milk in the saucepan you used for the potatoes until steaming but not boiling, then add the fish and poach for 3 min. Remove the fish with a slotted spoon and set aside, reserving the milk in the pan.

3 Melt the spread in the pan you used for the eggs, then stir in the flour, mixing well to form a thick paste. Add the wine and cook, stirring, for 2 min to reduce. Gradually add half the reserved milk, stirring well after each addition, until it’s incorporated. Add the remaining milk along with the capers and cook for a few min more, stirring until thickened and smooth. Add the potato chunks, spinach, chopped eggs and lemon zest, if using. Flake in the fish, stir gently to combine and season with freshly ground black pepper.

4 Spoon the mixture into a 1.5–1.6 litre pie dish and brush the rim with some of the beaten egg. Unroll the pastry over the top, then trim, leaving a 3cm excess all round. Roll up the excess pastry so it rests on the rim of the dish, then press down on it with a fork to crimp and seal. Brush all over with more beaten egg. Using the tip of a sharp knife, make a hole in the top for the steam to escape. You can use a few pastry offcuts to decorate the pie, if you like, sticking them on with beaten egg. Bake for 20–30 min until the pastry is golden.