Pre-heat oven to gas 4, 180ºC, fan 160ºC. Place pork, plums, jam, seasoning and sage in a large bowl, mix together well.
Roll out the pastry and using approx 17cm (6½in) bowl/saucer cut out 4 circles, re-roll and you should be able to cut one more.
Place a large spoonful of the mixture into the centre of the circle, lightly brush the edges of the pastry with a little water and fold the pastry around the filling. Press edges together and seal with a crimp pattern.
Brush with egg and milk glaze, and place on a non-stick baking tray (or use baking parchment). Bake in a preheated oven for about 25-30 minutes until pastry is golden brown.
Serve hot or cold, great with a fruity relish or chutney.
Haven't got time to cook this from scratch?
Try our ready-made version - Ginsters cornish pasty.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.