Make the Filling

Place flour in a large bowl, season with salt and ground black pepper, add the cubes of steak and kidney, and toss well in the flour until evenly coated.
Heat 2 tablespoons butter and oil in a large, flameproof casserole dish until the butter has melted. Add the meat to the fat in small batches and stir quickly for about 1 minute, or until the meat is browned. Set aside

Roll out the pastry and wide enough to cover the pie dish. Cut a tiny hole in the center to slip over the steam funnel if using.
Brush the rim of the pie dish with water and place a pie funnel in the center of the filling. Place the pastry over the dish and the funnel pressing it down, trimming to fit the rim of the dish. Crimp the edges using your thumb and first finger. If not using a pie funnel, just cut a small slash in the middle of the crust to allow steam to escape.

Brush the top with beaten egg. Bake for 40 minutes or until the pastry is crisp and golden.