Steak and Kidney Pie

Cut beef and kidneys into big cubes. In a bowl, mix the meat with the flour. Heat the oil in a heavy-based frying pan and brown the meat on all sides. Do this in batches so as not to overfill the pan. Transfer into a saucepan. Deglaze the frying pan with the wine and scrape with a wooden spatula. Pour this liquid into the saucepan. Sweat the minced onions in the frying pan and add to the meat. Season with the Worcestershire sauce, mustard, tomato purée, bay, thyme, salt and pepper. Cover the meat with water, bring to the boil, then turn down the heat to a gentle simmer. Cover and cook for about 1 1/2 hour, until the meat is tender. Check the seasoning and let the filling cool down. Sweat the halved mushrooms in a frying pan and add to the filling. Spoon in to a pie dish, brush the edges with yolk and cover it with the pastry. Make a little hole in the middle to let any steam out and make decorations with the trimmings. Brush with a mix of yolk and water to glaze and bake in a 200C oven for 30min until golden.