1. Tip the flour into a large bowl. Peel back the foil of the butter and grate it into the flour. Every so often, stir gently to coat the grated butter in the flour then carry on grating. Once all the butter is grated stir again then add 120-150 ml cold water and mix until the pastry comes together. Shape into a flattish round disc, wrap in cling film and put in the fridge for 20 mins.
2. To make the filling, melt the butter in a medium saucepan over a low heat. Add the leeks, the thyme leaves and a pinch of salt. Cover with a lid and cook gently for 10-15 mins until the leeks are soft. Once soft add the flour and mustard and cook for 1 min. Then add the stock and cream and simmer for 3-4 mins until thickened. Stir in the turkey, ham, onions and parsley and leave to cool.
3. Put the filling in a rectangular pie dish that’s about 24cm x 18cm x 5cm. Cover and chill in the fridge.
4. Heat oven to 200C/180C fan/gas 6. On a lightly floured work surface, roll the pastry into a rectangle that is the thickness of a pound coin. Trim 1 cm thick strips from the edges of the pastry and with a little beaten egg stick them to the edges of the pie dish. Brush the top of the pastry strips with a little egg wash then lift the rectangle of pastry onto the pie. Snip around the edges with a pair of scissors then use a fork or cutlery knife to crimp the edges.
If you like, re-roll the off-cuts and cut out shapes to decorate the top of your pie. Brush the top with egg wash then make a steam hole in the centre of the pie with a piping nozzle. Put the pie in the oven and bake for 20 mins then turn the oven down to 180C/160C fan/gas 4 and bake for another 30 mins until the pastry is crisp, puffed up and golden and the filling is piping hot.
ONE SERVING CONTAINS 1 OF YOUR 5-A-DAY PORTIONS