Steak and kidney is what I think of whenever pie is mentioned. The tender beef and tasty kidney in a rich oniony gravy is just perfect when packed inside a crispy hot water pastry crust - top and bottom, of course. It really is a British classic.
Stir the salt into the flour in a large bowl. Pour over half of the fat/water and stir it in until the water has been incorporated. Do the same with the other half of the water. Tip the dough out onto a worktop and knead it by hand to get any final bits of flour mixed in. Wrap it in plastic film and leave to cool. It needs to be about room temperature by the time you use it.
Peel the onions and chop into small bits. Sauté gently in some oil on medium heat for 5-10 minutes. You want the onions to be soft but not brown. By this time, your stock should be boiling and there may be some scum on the surface. Skim this off, then add the onions, salt, pepper and parsley. If you are using a pressure cooker, put the lid on, bring up to pressure and cook for 20 minutes. If you are using a regular saucepan, put a lid on it and simmer for about 3 hours, until the meat is tender.
Just before your beef is ready, chop the kidney into small pieces, making sure you get rid of any tubes or gristle. Fry them quickly in some hot oil to get them browned all over, then add them to the beef stew. Boil rapidly for about 15 minutes to get the liquid reduced by about half. Now sift in some flour (probably 1-2 tablespoons) and stir it in to thicken the gravy - if you don't have a sifter, you can sprinkle the flour in gently, a bit at a time, stirring all the while to disperse it. Taste for seasoning and add more salt or pepper if you think it needs it. Pour into a bowl or other container and stick it in the fridge to cool - it needs to be at room temperature when you add it to the pie, otherwise you'll get a soggy bottom.
Take the rest of the pastry, roll it out as before and press it into the pie dish. Trim off any excess pastry around the edge. Now spoon the filling into the base using a straining spoon. You want some gravy in the pie, but not so much that it's swimming with it. Keep the remaining liquid to make a pouring gravy - just thicken it by sifting in some flour, or you can make up some beurre manié (a paste of equal parts softened butter and flour) and cook some of that in.
Moisten the rim of the base with some cold water. Put the lid on and squeeze it against the base with your thumbs. Then lift up the rim so it's not sticking to the tin. If you like, you can do some fancy crimping - you'll have to watch the video for this because I can't really describe what I do!
When it's baked, let it cool for 5-10 minutes, then cut enormous wedges from it and serve with potatoes and steamed vegetables. Slosh a good bit of the gravy over the top.