This so very simple. Minimum ingredients if you cheat and just buy ready made shortcrust pastry like me 
Ingredients:
1 tbsp olive oil
1 onion, finely chopped
300g lamb, finely sliced – bite size
1 potato, peeled and diced
300ml lamb stock
1tbsp French mustard
500g ready made shortcrust pastry
1 egg, beaten
- Preheat oven at 200C/gas mark 6.
- Heat the olive oil on moderate heat and add the onion and lamb. Cook for about 5 minutes, stirring occasionally. Add the potato, reduce heat and cook for another 2 minute until beginning to brown, stirring occasionally.
- Stir in the lamb stock and add mustard. Cover and let it simmer for 15 minutes, stirring occasionally until the potato and lamb are tender. Set aside to cool.
- Divide the pastry into six and shape them into balls. Roll out each ball into 15cm diameter circle, about 5mm thick. Divide the lamb mixture into six and place in the middle of the rolled out pastry. Fold and pinch the pastry to seal it.
- Place the pasties on a baking sheet and brush each one with beaten egg. Place the tray into the middle of the oven for about 25 minutes or until the pastry is golden and crisps.
I prepared the lamb mixture the night before and and rolled out the pastry and filled in the mixture first thing in the morning. This is to save time so when I get home in the evening with Little Bee, I just glazed the pasties with egg and bang them in the oven and gave Little Bee her bath, so they were ready by the end of her bath and cooled down when she’s all dressed in her pyjamas.