Chicken and Leek Pie

Everyone loves pie! Especially in my house. This was a very yummy chicken and leek pie (or cock-a-leekie as we call it). I made the filling the night before, so that it was completely cooled to put the pastry lid on top. I don't make my own puff pastry, so just used some shop bought. Life is too short :) I had 5 licked-clean plates after this dinner, so very much a winner. The weather is so wet & windy at the moment, comfort food is needed.

2 tbsp vegetable oil
1 onion, finely chopped
2 medium leeks, washed, trimmed and thickly sliced
4 skinless chicken breasts, cut into bite-size pieces
1 garlic clove, crushed
150ml white wine
150ml chicken stock, hot
142ml carton double cream
Sprigs fresh tarragon, leaves picked and roughly chopped
375g pack ready-rolled puff pastry
1 medium egg

 Heat the oil in a large frying pan over a medium heat. Add the onion and leeks and cook for 4-5 minutes until softened.
Add the chicken pieces and cook, stirring, for another 4-5 minutes. Stir in the garlic, add the wine and bubble away until reduced by two-thirds. Pour in the stock and simmer until reduced by half. Add the cream and tarragon, bring to the boil, then simmer for 5-6 minutes until thickened. Season, then spoon into a 2.5-litre pie dish (or 4 x 300ml ovenproof dishes). Set aside to cool.
Brush a little water along the edge of the pie dish or dishes. Unroll the pastry and cut out a piece large enough to cover the dish or dishes. Press down the edges and trim off the excess. Snip a small hole in the centre of the pastry to let the steam escape. Put on a baking tray and chill for 15 minutes.
Meanwhile, preheat the oven to 220C/fan200C/gas 7. Beat the egg with a little salt, then brush over the pastry. Bake for 40-45 minutes (20-25 minutes if you are making individual pies) until the pastry is golden.