Ham hock, cider and green peppercorn pie

ham hocks 1 large or 2 smaller, about 2kg in total

bay leaves

peppercorns

butter

leeks 2, washed and chopped

plain flour

cider

double cream

wholegrain mustard

green peppercorns 1 tsp, rinsed and finely chopped

flat-leaf parsley ½ bunch, chopped

puff pastry

egg 1, beaten to glaze