Step 1

Begin by making the pastry. Put the flour into a mixing bowl, then remove the block of butter from the freezer and coarsely grate it into the flour. If the block is not grating well, dip the end into the flour first to help it grip. Use a round-bladed knife to mix together the butter and flour until each piece is well coated.

Step 2

Add 75ml cold water, 1 tbsp at a time, mixing constantly, until a rough dough forms and begins to clump together. Use your hands to bring it together by lightly kneading once or twice. You should be able to see lots of butter streaks – this will create layers. Wrap and chill for at least 20 minutes.

Step 3

Dust a worktop with flour and lay the pastry onto it. Roll out into a rectangle slightly larger than an A4 piece of paper. Fold ⅓ into the middle, then repeat with the other side. Finally, fold vertically to create a square of pastry. Rewrap and chill for at least 20 minutes, or until needed.

Step 4

For the filling, slice each chicken thigh into 3 and place into a medium-sized saucepan. Cover with the milk and add the bay leaf, then put the lid on and place over a low heat. Cook gently for 12-14 minutes – the chicken should have poached and will be cooked through with no pink meat and the juices running clear. Keep a close eye that the milk doesn’t bubble over and reduce the heat if necessary

Step 5

Use a slotted spoon to transfer the chicken pieces to a plate. Discard the bay leaf and set the milk to one side.

Step 6

Melt the butter in a large saucepan or a 24cm flameproof, ovenproof casserole. Add the leeks and sauté for 5 minutes. Add the flour and stir well to coat. Gradually pour in the poaching milk, stirring constantly until you have a smooth sauce. Add the sweetcorn and ham hock and season well.

Step 7

Use 2 forks to shred the chicken into large pieces, then add to the pie filling. If baking the pie in a different dish to the one used for the filling, transfer it to a 24cm pie dish. Let it cool to room temperature before adding the pastry.

Step 8

Preheat the oven to 220ºC, gas mark 7. Remove the pastry from the fridge, roll out on a floured surface and cut into a circle slightly larger than the casserole or pie dish. Use scissors or a sharp knife to snip a few slits in the top to allow steam to escape.

Step 9

Brush the lip of the pie dish with a little beaten egg. Transfer the rolled pastry onto the pie dish and press down gently over the filling. Make sure it is pressed against the sides of the dish firmly to prevent the filling from bubbling up around the edges. Brush with the beaten egg, then bake for 25-30 minutes – the top should be golden and crisp. Allow to stand for at least 5 minutes before serving.