Put the lamb/mutton shoulder on a roasting tray and roast for 25 minutes until golden. Reduce the oven to 150C/fan 130C/gas 2.
In a large casserole over a medium heat, add 1 tablespoon of vegetable oil and fry the onion, garlic and ginger and a pinch of salt for 10-15 minutes until really soft.
Add the spices and cook gently for another 5 minutes, stirring regularly.
Tip in the tomatoes, add the lamb/mutton (discarding any fat) and top up with enough water to cover.
Bring to the boil, put a lid on and put in the oven for 2 ½ hours.
Remove the lamb from the liquid and cool completely. Skim the liquid of excess fat and reduce until saucy. leave to cool.
Once cool, break the lamb into bite-sized pieces, discarding the fat and sinew.
Mix with the potato and enough of the reduced sauce to be nice and saucy and season.
Heat the oven to 220C/fan 200C/gas 7.
Butter 6 pie tins or tall ceramic ramekins roughly 10cm x 10cm, and roll out a block of pastry to a thickness of 4mm. Line each tin, leaving a 2cm excess.
Roll the remaining pastry out to a thickness of 4mm, cut out 10cm x 10cm circles and lightly score in a diamond shape.
Add the cold lamb mix to the lined tins and put the pastry circles on top. Brush the top with beaten egg and fold the overlaps over and crimp.
Make a small hole in the middle of the lid to allow steam to escape. Chill for 30 minutes.
To make the mango salad, toss all of the ingredients and season.
Bake the pies for 30-35 minutes until deep golden, then remove the pies from the oven and leave to cool for 10 minutes before carefully removing from the tins.
