Preheat the oven to 160C/375F/gas 5.
Heat the oil in the casserole, add the onion and sauté on a moderate heat until translucent and starting to take on a little colour.
Add the garlic, mushrooms, bay leaves, juniper berries, rosemary and thyme and continue to sauté for a few minutes. Remove from the heat and set aside.
Place the beef dripping in the frying pan and heat until sizzling hot. Add half the venison cubes and brown on all sides. Transfer to the casserole. Add a little more dripping to the frying pan and brown the remaining venison. Transfer to the casserole.
Add the flour and stir through.
Place the casserole on the hob and heat up a little before pouring in the beef stock and bringing to the boil. Immediately remove from the heat, cover with the lid and place in the oven for two and a half hours or until the meat is very tender.
Use a slotted spoon to transfer the meat and mushrooms to the pie dish.
Remove the bay leaves, rosemary and thyme sprigs from the remaining liquid in the casserole and place it over a high heat to reduce it to a thick, rich gravy. Pour over the meat and mushrooms and allow to cool to room temperature.
Place a pie funnel in the centre of the meat.
To make the pastry sift the flour and salt into the large mixing bowl.
Cut the butter into very small chunks, add them to the bowl and stir them in.
Add the cold water and bring together to a wet dough with a lumpy consistency.
Cover with clingfilm and place in the fridge for 30 minutes.
Place the dough on a floured work surface and shape into a rectangular block.
Roll the dough to a rectangle three times longer than it is short, keeping the edges straight and even. The rolled-out pastry should have a marbled effect from the lumps of butter.
Fold the top third down to the centre, then the bottom third up and over that.
Give it a quarter turn and roll out again to the original sized rectangle.
Repeat the folding, turning and rolling out 3 more times or until the marbling effect has disappeared. Fold once more and place in the fridge for 30 minutes.
Raise the oven temperature to 180C/350F/gas 4.
Remove the pastry from the fridge and roll out to 3mm thick.
Brush the edges of the pie dish with beaten egg.
Place the rolled-out pastry over the meat. Crimp around the edges and trim away any excess pastry. Use this to make leaves (or what you will) to decorate the pie which can be stuck on with beaten egg.
Make a hole in the pastry above the pie funnel so the funnel peeps through and brush the top of the pie with beaten egg.
Place the pie in the oven and bake for 45-50 minutes until golden brown.
Remove from the oven and leave to cool for 15 minutes before serving. It is very good served with potato and celeriac mash, and a dark leafed cabbage.
