Step 1

To poach the chicken, place chicken marylands, dark green leek tops, peppercorns, bay leaf and 2L (8 cups) cold water (or enough to cover) in a large saucepan over high heat.

Step 2

Bring to the boil, then cover with a lid, leaving a small gap. Reduce heat to low and cook for 1 hour or until chicken is cooked through.

Step 3

Remove chicken from pan and set aside. Strain the cooking liquid into another saucepan, discarding the leek, pepper and bay. Place pan over medium heat and cook for 30-40 minutes until reduced by half. Set aside to cool.

Step 4

Meanwhile, to make pastry, place the flour, xanthan gum and 1 tsp salt in a food processor, then whiz to combine.

Step 5

Add the cheese and butter, and whiz to combine. In a separate bowl, combine the egg, mustard, creme fraiche and 1 tbs cold water. Add to the food processor and whiz until the mixture forms a soft dough.

Step 6

Turn dough out onto a lightly floured surface and divide into two equal pieces, one slightly bigger than the other. Flatten into discs, then enclose in each plastic wrap and chill for 1 minute or until firm.

Step 7

Once the chicken is cool enough to handle, shred the meat into bite-sized pieces, discarding bones.

Step 8

Heat the oil in a large frypan over medium heat. Add sliced leeks and thyme, and season. Cover and cook, stirring occasionally, for 10 minutes or until leeks are tender but still green.

Step 9

Add chicken, ham, creme fraiche and 300ml chicken stock to pan. Bring to a simmer and season to taste. Combine cornflour and 2 tbs cold water in a bowl until smooth, then stir into the sauce and simmer for 2-3 minutes until thickened.

Step 10

Remove from heat and set aside to cool.

Step 11

Roll out larger pastry portion on a lightly floured surface until 3mm-thick and use to line a 23cm pie pan, leaving a little overhang. (If you have any rips or tears, just pinch them back together). Place the cooled chicken filling into the middle of the pastry base.

Step 12

Brush the edges with the egg yolk glaze, then roll out the remaining pastry until 3mm-thick. Cut a couple of slits in the pastry to let out the steam. Top the pie with the pastry, pressing the edges together.

Step 13

Trim the excess pastry, then crimp the edges to seal. Use excess pastry to create decorations, if desired. Brush pie all over with egg glaze, then chill for at least 10 minutes.

Step 14

Place a large baking tray in the oven and preheat to 200°C. Glaze pie again, then place on hot tray. Bake for 45 minutes or until dark golden and a skewer inserted into the centre comes out hot.