Calum Franklin’s ultimate fish pie

Method

1. To make the topping, put the potatoes in a pan and add enough salted water to just cover them. Bring to the boil, then reduce the heat and simmer until the potatoes are tender. Drain and allow to steam dry for a few minutes in a colander set over the hot pan. Add the 200ml milk, 100ml double cream and 60g butter to the pan, then mash the potatoes until smooth. Mix in the egg yolks and salt, then set aside.
2. Next make the filling. Pour the milk and cream into a medium pan and bring to a simmer. Drop the diced fish and peeled prawns into the simmering liquid and poach for 2 minutes. Drain the fish, reserving the poaching liquid; set both aside.
3. Wipe out the pan and add the butter, bring it to a bubble over a medium heat, then whisk in the flour. Reduce the heat to low and cook for 8 minutes, whisking continuously. Gradually add half the reserved poaching liquid and bring the mixture back to a simmer, whisking continuously to prevent lumps forming. Add the remaining poaching liquid and cook until thick and smooth. Mix in the peas, capers, chives, parsley, mustard and salt.
4. Return the drained fish to the pan and lightly fold into the sauce, being careful not to break it up. Spoon the mixture into a deep ovenproof dish and level it (see Make Ahead).
5. Spread the mash topping over the pie mixture, taking it right to the edges of the dish, then ruffle the top with a fork to create texture. Scatter the grated cheese evenly over the surface of the pie.
6. Heat the oven to 200°C/180°C fan/ gas 6. Put the dish on a large baking sheet in the hot oven and bake for 30-40 minutes or until the sauce is bubbling up at the sides and the potato topping has a crisp golden crust. Serve (see tip).