Ingredients:

2.5kg (5 1/2lb) cooked bone-in ham joint
40g (1 1/2oz) butter
500g (1.1lb) leeks, sliced
250g (10 1/2oz) mushrooms, sliced
2 cloves garlic, finely chopped
2tbsp plain flour, plus extra for dusting
500ml (17fl oz) chicken stock
80ml (3fl oz) crème fraîche
15g (1/2oz) chopped fresh tarragon
a pinch of salt
freshly ground black pepper
375g (12 1/2oz) pack lighter ready rolled puff pastry
1 egg, beaten

Method:

1. Remove 600g (1lb 3oz) of ham from the cooked joint and cut it into bite-sized chunks. Wrap the leftover joint in foil or place in a lidded airtight plastic box and store in the fridge. Use within 2 days.
2. Preheat the oven to gas 7, 220°C, fan 200°C. Melt the butter in a lidded frying pan over a medium heat, add the mushrooms and cook for 5 minutes, then stir in the leeks, cover and cook for 10 minutes more, until softened, adding the garlic for the last 2 minutes.
3. Next stir in the flour, then turn up the heat and gradually pour in the stock, stirring all the time. Bring to the boil and cook for a couple of minutes until the mixture thickens a little. Remove from the heat and add the crème fraîche, tarragon and ham and season to taste. Spoon the filling into a 2 litre (3 1/2 pint) pie dish and place it on a baking tray.
4. On a floured surface, unroll the puff pastry. Cut a pastry strip the same width as the lip of the dish, wet the edge of the dish with a little of the beaten egg and fix the strip around it. Brush the top of the pastry strip with egg, then carefully place the remaining pastry on the dish. Trim the edges of the pastry and crimp to seal. Cut a slit in the middle of the pie to allow the steam to escape. Use any leftover pastry to cut out shapes to decorate the pie.
5. Brush the pastry with the beaten egg and bake for 25‑30 minutes until risen and golden.