1 tbsp olive oil
1/2 x 160g pack cubetti di pancetta with herbs
150g mushrooms, thickly sliced
2 x 300g pouches mushroom soup or 400m1 Bisto chicken gravy
3 cooked chicken breasts, skin removed and roughly shredded
2 tsp cornflour
A large handful of roughly chopped tarragon
1 x 375g pack ready-rolled puff pastry
1 large egg yolk
Heat the oven to 220C/Gas Mark 7. Heat the oil in a large frying pan and fry the pancetta over a moderate heat for a few minutes. Add the mushrooms and cook for a further 5 minutes or until the mushrooms are beginning to brown, then stir in the soup or gravy, chicken, cornflour and tarragon.
Bring to the boil, reduce the heat and simmer for 3-4 minutes until thickened slightly.
Season to taste, transfer to the pie dish and allow to cool slightly.
Meanwhile, unroll the pastry and cut a piece for the lid. Cut the trimmings into long 2.5cm wide strips. Dampen the rim of the pie dish with water, then place the pastry strips along the edge in a single layer. Brush with a little more water and put the pastry lid on top (use any remaining pastry to decorate the top, if you like).
Press the edges firmly to seal, then trim and flute them by gently pressing with the back of a knife. With a sharp knife. make two cuts in the centre of the pastry to let steam escape. Then brush with the egg yolk.
Bake for 25-30 minutes or until lightly golden.