Corned Beef Pie is easy and eats well with beans or salad and is GREAT cold for picnics.
First you need a pie dish about 8inch diameter and at least 1 inch deep.

If making your own short crust do so, so that it has half an hour to rest in the fridge: 8oz self raising flour
4oz butter
Salt
Water to mix
Wrap in cling film and refrigerate (or freeze for a later date)

Use left over or instant Mash (Mr Mash is best)
Chop and fry 1 onion until soft not brown
Add the can of corned beef to the pan
Then add the mashed potato
Season with salt and white pepper to taste (or crumble in a dry Oxo cube if desired)
Thoroughly mix whilst heating.
Allow to cool while you roll half the pastry and put it over your pie dish. Add the filling.

Roll out the top and place it over the filling, Crimp the edges with your thumb and trim off any excess (you can make a wee decoration for the topout of the scraps 😉 and brush with egg if you want a sheen. Preheat the oven to 170 C and cook the pie for 45 mins to 1 hr until well golden.