Sear the beef fillet

• Season the beef fillet generously with salt and black pepper.
• Heat the olive oil in a frying pan over high heat and sear the fillet on all sides until browned.
• Remove from the pan and brush all over with English mustard, then set aside to cool.

Make the mushroom duxelles

• Blitz the chestnut mushrooms in a food processor until finely chopped.
• Melt the butter in a pan and soften the shallots, garlic and thyme.
• Add the mushrooms and cook until all the moisture has evaporated, then season and cool.

Wrap the fillet

• Lay the Parma ham slices overlapping on a sheet of cling film.
• Spread the cooled duxelles over the ham in an even layer.
• Place the beef fillet on top and roll tightly using the cling film to enclose it, then chill to firm up.

Encase in puff pastry

• Roll the puff pastry out on a lightly floured surface into a rectangle.
• Brush the edges with egg wash, unwrap the beef and place it in the centre.
• Fold the pastry over to seal, trim any excess and brush the top with egg wash.

Bake the Wellington

• Heat the oven to 200 °C.
• Place the Wellington on a baking tray and bake until the pastry is golden and the beef reaches 55 °C in the centre.
• Rest before slicing and serving.