Anything Goes, Christmas/New Year Leftover Pie

We have a few friends around on Christmas Eve and there is always food left over, so one of our staples on Boxing Day is a "leftovers pie".
It depends what is left (and what is in the fridge/freezer) but is usually chicken, lamb chops/sausages, venison/venison sausages, steak, salami, and sometimes goose and rabbit

Supplies

Meat - - - various (see above)
Onion
Mushrooms
Pastry
Egg (for Egg wash)
Gravy
Cranberry jelly
Salt and pepper
Margarine for greasing tin
Pie tin
Greaseproof paper

Prepare the Tin

I like to go a bit overboard with the tin, so I grease it with Margarine, line it with Greaseproof paper then grease the Greaseproof paper.
This sucka ain't gonna stick!

Line the Tin With Pastry

I could make my own pastry, but who's got time for that, so shop bought pastry sheets, savoury shortcrust or puff pastry, whichever are available.
Bottom first, then sdes, joined with a bit of egg wash and pressed together with a fork

The Filling

First up chopped up an onion and some mushrooms and softened in a frying pan with a little olive oil

Chop Up the Meat and Add to the Pan

Chopped up all the meat into little pieces added to the pan, gave it a good stir and then added a bit of Gravy with some Cranberry jelly in it.

Transfer the Mix to the Pastry Case

Press it well into the corners so there are no voids and fold the sides over.

Add a Top Crust

Put on the top pastry, a couple of decorative leaves and an egg wash to joint the top to the sides and as a glaze.

Preheat Oven to 350F

Bake until pastry is cooked (about 20 minutes)
Release from tin. Enjoy.
Can be eaten hot or cold