Make the pastry. Combine the flour and turmeric in a mixing bowl and rub in the dripping or lard and butter using your fingertips. This can also be done in a food processor, stopping the blade once the mixture starts to look like breadcrumbs. Gradually add the icy water until the mixture starts to come together to form a firm dough. Roll the dough into a ball and rest in the fridge for 30 minutes.
Preheat the oven to 180°C, fan 160°C, gas 4. Make the filling. Put the chicken and vegetables in a large bowl and add the jerk paste or seasoning and Worcestershire sauce then season.
Remove the pastry from the fridge and cut into quarters. Dust the work surface with a little flour and roll each quarter out into a disc about 21cm in diameter, using a small plate as a template.
Brush the edges with the beaten egg then put a pile of filling on each disc, topped with a little piece of butter. Fold the dough over to make a semi-circle, pressing hard to seal the edges. Crimp to seal then transfer to a baking sheet lines with baking parchment. Brush all over with the remaining egg and bake in the oven for 40-45 minutes until golden.
Cook's tips: to save time prepare all the vegetables the night before, cover with cold water and store in the fridge. Drain and pat dry with kitchen towel before using.
If you have any leftover roast beef, you could use this instead of the chicken.