With my Austerity hat on, I would like to announce that you can get a large pork joint for about a fiver from most supermarkets, and that will do a Sunday roast and make a pork, pea and mushroom pie afterwards for Monday. Yum yum yum. Here we go.
For pork, pea and mushroom pie, chop leftover pork and bacon into small cubes, fry up in pan for a couple of minutes with a bit of chopped onion, add about about 8oz halved or quartered mushrooms depending on size, and add 2-4 oz frozen peas. Pour over some stock or hot water with a few gravy granules added. Be careful it's not too runny - add some more gravy granules if it's going wrong. Worcestershire sauce or leftover wine add to the flavour, as do: crushed juniper berries, bay leaves, sage, but they are optional. (I know leftover wine is an unknown concept for many MNetters, up there with leftover chocolate). Simmer for a couple of minutes and then put the whole lot into a baking dish or tray. Top with either shortcrust pastry and bake until the pastry is golden, or put a savoury crumble on top - 8 oz each of margarine and flour rubbed together, add a few oats, salt and pepper, and a handful of grated cheese. You can also top it with mashed potato and bake in the oven for a bit if you like, until the potato starts to turn golden.
Now a chef would suggest things like using pancetta, using home made pork or ham stock, using a bouquet garni of fresh herbs, using a beurre manie to thicken a sauce if you weren't reducing it, adding an egg yolk to the shortcrust pastry and using butter to give a richer crust, and all sorts of things like that. But the improvement in taste would only be 10% and you would be increasing the time, fuel cost, and general expenditure.
This is the dilemma JO has, to be fair. He is a chef so if he started banging on about gravy granules and frozen peas and so on, people would think he had sold out completely. But the outcome is that his recipes are nice to have, rather than day to day. At it will ever be thus.