Directions

1. Heat the oil in a flameproof casserole. Add the onion and cook until soft, about 5 mins. Meanwhile, season the beef and toss with the flour and mustard powder. Push the onions to the edge of the pan and add the beef. Brown the meat, then add the puree and cook for 2 mins more. Add the remaining filling ingredients, except the mushrooms. Season, stir well, then cover and simmer for 2 hrs, stirring occasionally.
2. Add the mushrooms and cook without a lid until the mushrooms are soft and the liquid has reduced to a thick gravy, about 10 mins. Leave to cool while you make the pastry.
3. Tip the flour, mustard powder, suet, cheddar and 1/2 tsp salt into a food processor. Blitz until there are no visible lumps of suet, then dribble in all but 1 tsp of the egg (you'll need this for glazing the top) and enough water, 1 tbsp at a time, to bring the mixture together as a dough. Tip onto a floured work surface and knead briefly until smooth. Remove 1/4 of the pastry, wrap in cling film and set aside. Divide the remaining pastry into 2 lumps, on a lightly floured surface, roll out to approximately 0.5cm thickness, and use each piece to line a 500ml pie tin, leaving some pastry hanging over the edges. If you want to cook the pies now, heat oven to 200C/180C fan/gas 6.
4. When the filling has cooled down, divide the mixture between the 2 cases. Roll out the remaining pastry and cut out 2 lids to fit, saving the trimmings. Brush the inside edges of each pie with a little egg, then press on the top. Trim the overhanging edges and crimp to seal. Brush the top of the pies with more egg and cut a small air hole in the top of each one. Use the pastry trimmings to decorate.
5. Put the pies on a baking tray, and bake for 45 mins until the pastry is golden brown and the filling is hot.Alternatively, cover the uncooked pies with cling film and freeze for up to 2 months. Cook from frozen at 200C/ 180C fan/gas 6 for 1 hr.Serve with carrots and broccoli, if you like.