Preheat the oven to 200C/ 400F/ gas 6.
Make the filling first. Add some salt and pepper to the flour and use to coat the steak and kidney.
Pour the oil and butter into a large saucepan and set over medium-high heat. Put in the steak and kidney then fry for about 5 minutes, until brown.
Stir in the onions and fry for another 3 or 4 minutes.
Mix in the bay leaves, stout and stock.
Add the gravy and stir well. Cook for another 2 or 3 minutes, until it thickens
Put a lid on the pan and stew for about 1 hour 30 minutes, until tender.
While the filling is cooking you can make the pastry. Combine the bread flour, salt and butter in a bowl. Dig a well in the center then pour the water slowly. Mix together into a dough.
Flatten into a rectangle. Mark into thirds then fold back the first and last thirds onto the middle one. Turn dough 90° clockwise and repeat. Take the same steps one last time then put in the refrigerator for about 30 minutes.
Allow the meat to cool down a bit before pouring into a pie dish. Lightly flour your work surface. Flatten the pastry then cut into a piece slightly larger than the size of the pie. Make a strip with the trimmings to fit the rim of the dish.
Brush the beaten egg over the rim of the pie dish. Place the pastry strip on top then brush again. Put the lid on top, scrunching the edges. Brush over with the rest of the egg then cut a slit in the top.
Put in the oven for about 30 to 40 minutes, until the pie becomes golden.
Serve alongside buttered spring cabbage and mashed potato.