2 - Get a good seal on the beef. For this you want a large pan, and very hot. Leave some space in the pan -if you crowd the beef there is nowhere for the steam to go, and it will stew rather than caramelise. The caramelisation gives you the depth of flavour in your beef pie. Close your kitchen door or you may set off the smoke alarm in your house.3 - Deglazing. When you have lifted out your sealed beef in to your casserole dish, add a little more oil and cook the onions till the start to caramelise. As they caramelise they will lift the sediment from the beef you sealed before. Cook the mushrooms afterwards in the same pan, and again, you want them to have space in the pan so they colour on the outside rather than steaming. This colour will give you a richer flavour. Once they are well coloured and transferred to the casserole dish, add a litte of the ale in to the pan to lift off any sediment - deglazing - and add this to your casserole. This is the way you maximise your flavours.
4 - Use a holey baking tin.
Once your beef is cooked (between 4 and 7 hours for shin. The most I ever cooked it for was 9 hours and it melted) and cool, you are ready to make your pie. A perforated tin such as the one above allows the bottom of the pie to cook properly so the pastry doesn't sweat - crispy instead of soggy: the perfect pie. It is also easy to undo as the base lifts out - saving you from breaking it.
5a - Make sure your gravy you put in the pie is very thick (with extra cornflour to thicken if neccessary). This means less steam, so the pastry will hold together without bursting.
5b - Seal it wth an egg. Before putting the lid on, brush the top of the pastry that forms the base with beaten egg. Put the lid on squeezing the two layers together in your fingers. Refrigerate for 20 minutes to half an hour so the join seals. This is much stronger, and less likely to burst open when cooking.
You could cut out a square or oval of shortcrust or puff pastry, egg wash it and cook it for 15 - 20 minutes and place it on top of your beef once cooked such as the below. This is more ideal for your guests who like pastry but not too much of it to fit in with their diets.