This is a great recipe for this time of year while chestnuts are falling from sweet chestnut trees (if you can get them before the squirrels) though you can always cheat by getting ready cooked vac packed ones.
450g/1lb braising steak
30ml/2tbsp plain flour seasoned with salt and freshly milled black pepper
45ml/3tbsp rapeseed or sunflower oil
1 red onion, peeled and sliced
100g/4oz peeled chestnuts, halved
150ml/¼pint beef stock
5ml/1tsp brown sugar
5ml/1tsp wholegrain mustard
½ x 500g pack prepared puff pastry
1 egg, beaten
Place the seasoned flour and seasoning into a large plastic food bag. Add the beef in batches and shake to coat.
Heat the oil in a large non-stick frying pan and cook the beef in stages for 4-5 minutes until brown on all sides. Spoon into a 1.2L/2pint ovenproof casserole dish suitable for the hob and oven.
In the same frying pan fry the onions and chestnuts for 2-3 minutes. Spoon into the casserole dish with the beef.
Add the rest of the ingredients, turn up the heat and boil then cover, turn down the heat and cook on the hob or in a preheated oven at Gas mark 3, 170°C, 325°F for 1-1.5hours.
Remove the casserole from the hob or oven and turn up the oven to Gas mark 5, 190ºC, 350ºF.
Spoon into a 1.2L/2pint ovenproof pie dish.
For the topping, roll out the pastry in a large square on a lightly floured surface to about the thickness of a pound coin. Cut the pastry lid large enough to cover the dish.
Spoon the filling into the casserole dish, dampen the edges with water and cover the top with a pastry lid. Cut a small slit on top of the pastry for the steam to escape. Put the pie on a baking tray then brush the pastry with the beaten egg.
Cook for 25-30 minutes, or until the pastry is golden.