Make the Minced Beef Filling
Traditional pie and mash shops don't pre-cook their fillings, they simply add seasoned beef to the pie and it cooks in the very hot oven. I'm a little nervous of that approach so I do pre-cook the beef. Add the mince to a saucepan and cover with hot beef stock. Season with salt and white pepper. Simmer for 15 minutes until there is not much liquid left. If you like you can add a splash of gravy browning (a flavourless liquid caramel) to deepen the colour, but nothing else is added in a traditional pie.
Remove from heat and allow to cool completely - you don't want to be adding hot filling to pastry, it'll create a soggy bottom.
Pastry
Strangely, East End pies are made using 2 different pastries - the bottom is a suet based pastry, while the top can be ordinary shortcrust. Puff pastry is no-no.
Make the Suet Pastry
Mix the flour, suet and salt together in a large bowl. Add just enough water to bring it together as a ball of dough that leaves the bowl clean. Take it out of the bowl and knead on a floured surface until it develops a little elasticity - about 5 minutes. Wrap in plastic film and leave to rest.
Make the Shortcrust Pastry
Cut the butter into small chunks. Put the flour in a bowl, stir in the salt, and then rub the butter in with your fingertips. You should end up with a mixture that looks like coarse sand. Stir in just enough water to make it come together in a ball, then wrap it in plastic film and set it aside to rest for about 30 minutes.
Make the Liquor / Parsley Sauce
Dissolve a fish stock cube in hot water, bring to the boil and reduce to a simmer. Mix water and flour and stir well to make a smooth slurry. Add this to the stock along with the finely-chopped parsley. Stir well and keep on stirring until the sauce has thickened.
Taste for seasoning - add salt if needed.
Assemble the Pies
East End pies are always individual ones, and they are cooked quickly at very high temperature. You'll need some individual-sized pie dishes or foil containers. Flour the inside of the dishes well to prevent sticking. Heat your oven to 200°C (392°F) fan, 220°C (428°F) conventional, gas 10. Or as hot as it will go, basically.
On a floured worktop, roll out shortcrust pastry for your lids. It should be about 3-4mm (just under a quarter of an inch) thick. If you have a cutter or bowl that is the same outside diameter as your dishes, use that to cut lids. Otherwise cut around an upturned pie dish with a knife.
Roll out suet pastry for the bases. Gently press the pastry into each dish and trim off any excess pastry.
Fill each pie casing with the cooled minced beef filling. Moisten the rim of the base with cold water and put a lid on. Press it down all around using your hand like a claw.
East End pies are not glazed. Put then in the oven and bake for 12 minutes. It's quite likely you will get some scorched bubbles on the top - this is to be expected.
Make the Mashed Potatoes
Peel the potatoes and cut them into chunks. Bring a pan of salted water to the boil and cook the potatoes for 10-15 minutes until tender. Drain the liquid off and season with salt and pepper. Mash the potatoes until smooth - no milk, no butter, but you can add a little of the cooking water it the mash is too stiff.
Serve your Pie Mash and Liquor
Tip a pie out onto a plate. Scoop some mash onto the plate. Pie shops do this really quickly by scraping the mash onto the edge of the plate with a spatula - it looks a bit like a ski slope. Smother the mash with liquor and drizzle with chilli vinegar.