Method

1. Preheat the oven to 190C/375F/Gas 5.

2. Heat the butter and one tablespoon of the oil in a large frying pan over a medium heat. Add the onion and fry for 4-5 minutes, or until softened but not coloured.

3. Add the mushrooms and the garlic, reduce the heat to low and continue to cook for 15-20 minutes, or until the moisture from the mushrooms has evaporated. Season, to taste, with salt and freshly ground black pepper. Transfer the pan contents to a bowl and set aside.

4. Using a very sharp knife, make a deep incision along the length of the pork fillet. Stuff the fillet with the strips of black pudding and season, to taste, with salt and freshly ground black pepper.

5. Heat another tablespoon of the oil in the pan used to cook the onions and mushrooms. Add the stuffed pork fillet and fry for 3-4 minutes, turning regularly, until sealed and lightly browned all over. Remove the pan from the heat and set aside.

6. Dust a work surface with a light coating of flour and roll out the puff pastry to a rectangular shape approximately 20cm x 30cm/8in x 12in in size (it needs to be a little longer than the length of the pork fillet and wide enough to wrap around it). Trim the edges, reserving the offcuts.

7. Lay the slices of ham on top of the rolled-out pastry, leaving a 1cm/½in pastry border around the edge. Spread the mushroom mixture in a thin layer on top of the ham. Place the pork fillet in the centre of the pastry rectangle (reserve the pork juices in the pan).

8. Brush the edges of the pastry rectangle with a little beaten egg, then wrap the pastry around the pork fillet to form a large sausage shape. Press the ends of the pastry together to seal. Decorate the top of the pastry parcel with the pastry offcuts, then brush all over with more beaten egg.

9. Transfer the pork Wellington to a non-stick baking tray and bake for 15 minutes.

10. Reduce the oven temperature to 170c/340F/Gas 3 and continue to cook for 10 minutes, or until the pastry has risen and is golden-brown. Remove from oven and set aside to rest for 10 minutes (keep warm).

11. Meanwhile, return the pan containing the pork juices to a low to medium heat. Add the remaining tablespoon of vegetable oil and fry the apple slices for 4-5 minutes, or until softened and golden-brown.

12. Add the Dijon mustard, chicken stock, sage leaves and sherry and bring the mixture to the boil. Reduce the heat until the mixture is simmering and simmer until the volume of liquid has reduced by half and the sauce has thickened. Stir in the cream until warmed through and season, to taste, with salt and freshly ground black pepper.

13. To serve, cut the pork Wellington into thick slices and place onto serving plates. Spoon over the creamy apple sauce. Serve with steamed green beans and new potatoes.