Preheat oven to 180C/350F/gas 4.
Grease the tart tin with butter.
To make the pastry sift the flour and salt into the mixing bowl or food processor bowl.
Add the butter and lard and rub in (or process if using a food processor) until the mixture resembles fine breadcrumbs.
Break the egg into a cup and add the ice cold water and whisk together.
Add to the pastry mix and bring together to make a dough, adding more water if the dough is too dry. If using a processor add the egg mixture and whizz until the mixture forms a ball of dough.
Wrap with clingfilm and place in the fridge for 30 minutes.
Meanwhile, place a little lard in the large frying pan and heat until very hot. Add the minced lamb and fry until browned. Transfer to the casserole and add the remaining filling ingredients in the order set out.
Stir, bring to the boil and then simmer gently for an hour until the meat is tender and the dried fruit soft and plump. Keep stirring the mixture to prevent it sticking and burning to the bottom of the pan. The liquid should have reduced to very little.
If the mixture is too sloppy, strain through a sieve.
Allow to cool to a stiff, sticky consistency.
On a lightly floured work surface roll out a little more than half the pastry and line the tart tin with it.
Fill with the meat mixture.
Brush the top edges of the pie base with a little water.
Roll out the remaining pastry and use a knife to cut slits in a geometrical design of your choice. Place the pastry over the pie and stretch out a little to open up the slits. Seal the edges by crimping.
Place in the preheated oven and bake for 30 minutes or until the pastry is golden.
Remove from the oven and allow to cool a little before removing the pie from the tin. Carefully transfer to a serving plate. The pie can be eaten warm or cold.
