Step-by-Step Instructions

1. 1.Poach Chicken Breasts

   Bring a pot of water to a slow boil. Add 2 medium-sized chicken breast fillets to the boiling water. Bring the water back to a boil. Once boiling, cover the pot with a lid and turn off the heat completely. Set a timer for 15 minutes and let the chicken sit in the hot water. After 15 minutes, carefully remove the chicken breasts from the water and place them on a cutting board. Using two forks, shred the chicken breasts along their natural grain. Set aside.

2. 2.Prepare Pie Filling

   Melt 30g / 1oz butter in a medium-sized saucepan over medium heat. Add 100g / 3½oz finely chopped leek to the melted butter and stir-fry for about 5 minutes until soft. Add 3 finely chopped garlic cloves to the leeks and stir. Season with salt and black pepper to taste. Add 30g / 1oz plain flour to the pan and stir to combine, creating a roux. Add 15ml / 1tbsp apple cider vinegar and stir. Add 150g / 5½oz mushrooms to the pan and stir. Pour in 400ml chicken stock, adding it in two halves and stirring well after each addition. (Optional) Add 1 tsp wholegrain mustard and stir. Add 75ml double cream and stir to combine and thicken the filling. Stir in 30g / 1oz chopped parsley. Remove the filling from the heat and let it cool completely. You can place the pan in a sink of cold water to speed up cooling.

3. 3.Make Flaky Pastry

   Place 380g / 13½oz plain/all-purpose flour in a wide bowl. Add 8g / 1tsp salt and mix it into the flour. Make a well in the center of the flour and place a box grater in it. Take 250g / 8.8oz frozen unsalted butter, coat it in flour, and grate it through the large holes of the grater into the flour. Keep dipping the butter in flour to maintain grip and prevent sticking. Once all butter is grated, quickly mix the grated butter and flour thoroughly with your hands. Place the bowl in the fridge for at least 15 minutes to chill. Remove the bowl from the fridge. Gradually add 140g / 140ml ice-cold water, mixing with a dinner knife first, then with hands, until the dough comes together and is workable but not too wet. Divide the dough into 4 equal pieces, each weighing approximately 192g. Form each piece into a small disc, place them in a food bag, and refrigerate for at least 30 minutes.

4. 4.Assemble the Pies

   Preheat your oven to 170°C / 340°F / Gas mark 3. Grease four 5-inch individual non-stick pie tins with lard or butter. Prepare an egg wash by whisking 1 egg with a dash of milk. Lightly dust your work surface with flour. Take one pastry disc from the fridge, reshape it into an oval, and dust lightly with flour. Roll out the pastry using an adjustable rolling pin with a 3mm spacer (or to about 3mm thickness) into a large egg shape, wide enough to cut two circles. Using a 16cm pastry cutter, cut out a large circle for the base of the pie. Using a 14.5cm pastry cutter, cut out a smaller circle for the lid of the pie. Place the larger pastry circle over one of the greased pie tins and line it up. Using your fingers, manipulate the pastry down into the tin, ensuring it reaches the corners. Use a small spare piece of pastry to push the base pastry firmly into the corners of the tin. "Dock" the pastry by pricking a few holes in the base with a fork to prevent it from puffing up during baking. Fill the pastry case with the cooled chicken and leek filling, filling it just below the top of the pastry to allow for expansion during baking. Gently tap the tin on the bench to even out the filling and release air bubbles. Brush egg wash all around the rim of the pastry base. Place the smaller pastry circle (lid) on top of the filling and line it up. Gently press it down all the way around. Using your fingers and thumb, crimp all around the edge of the pie to create a good seal. Trim off any excess pastry using a dough knife or the back of a blade. Go around the pie again to tidy up the edges. Cut two or three vent holes in the middle of the pie lid. Repeat the assembly process for the remaining three pies. Brush the tops of all four pies with egg wash, being careful not to get any egg wash between the pastry and the lip of the tin.

5. 5.Bake the Pies

   Place the assembled pies into the preheated oven. Bake for 50 minutes. Once baked, remove the pies from the oven. Let them sit in their tins for 10 minutes before attempting to remove them. Carefully remove the pies from the tins and serve.