Chicken, leek and tarragon pies

Method

1. For the filling, put the chicken in a large pan, cover with cold water, then add the celery, carrot, peppercorns and tarragon sprigs. Bring to the boil, then simmer for 45 minutes or until the chicken is cooked through. Remove the chicken and set aside to cool. Strain the stock, discard the solids, then put the stock back over the heat to boil and reduce for 10 minutes. Remove from the heat and leave to cool.
2. Meanwhile, make the pastry. Sift the 500g flour and the salt into a food processor. Pulse quickly to combine, then add the cubed butter and pulse until the mixture has the consistency of fine breadcrumbs. Add 6-7 tbsp cold water, pulsing until it just comes together.
3. Turn out onto a floured surface and knead briefly until smooth, then shape into a flat disc, wrap in cling film and chill in the fridge for 30 minutes. Heat the knob of butter and the oil in a sauté pan, then soften the onion and leek for 10 minutes. Stir in 1 tbsp flour, then take off the heat and cool.
4. Remove and discard the chicken skin. Tear the meat from the bones and shred into a large bowl. Mix 300g of the chicken (save the rest for stir-fries, tarts or pasta) with the chopped tarragon, the onion and leek mixture, the cream and 100ml of the reserved stock (freeze the rest to use for other recipes). Season.
5. Preheat a baking sheet in the oven at 220°C/fan200°C/gas 7. Take the pastry from the fridge, remove one-third and set aside. On a lightly floured work surface, roll out the remaining two-thirds to the thickness of a pound coin. Cut out 12 x 11cm circles (re-rolling the pastry if need be) and use to line a 12-hole muffin tin, allowing the excess pastry to fall over the sides. Spoon the filling into the moulds.

6. Roll out the reserved pastry on a lightly floured surface and cut out 12 x 8cm circles to use as lids. Brush the pastry-mould edges with a little beaten egg, put the lids on top and seal well. Trim any excess pastry and crimp the edges. Brush with more beaten egg and make a hole in each lid (to release steam).

7. Put on the preheated baking sheet and cook for 25 minutes until the tops are golden and crisp and the filling is piping hot.(Cover with foil if the pies brown too soon.)

8. Remove from the oven, cool for 5 minutes in the tin, then carefully remove the pies. You can eat them right away, but for your picnic, allow to cool completely, then wrap each one in baking paper and chill for up to 2 days until needed. Let them come to room temperature before eating.