

Slice the tenderloin down the middle lengthwise, creating 2 separate pieces. Trim the pork tenderloin of any excess fat and silver skin.Place the apple rings into the bowl of a mini food processor and process for 30 to 45 seconds or until they are the size of a medium dice. Whisk the egg and water in a small bowl and set aside.Place a rack in the upper third of the oven and heat to 400 degrees F.To make the sauce, bring the cream to the boil, add the mustard and reserved mushroom mixture, and remove from the heat.Allow to stand for 10 mins before serving in thick slices. Brush the wellington with a little more egg yolk and cook for 35-40 mins until golden - the pork will be just pink in the middle.

Chill for at least 30 mins or up to 24 hrs.

Glaze all over with more egg yolk and, if you like, mark the wellington using the back of a knife, taking care not to cut into the pastry. Seal the rim with the edge of a spoon handle. Using a rolling pin, lift and drape the larger piece of pastry over the fillet, pressing well into the sides. Brush the pastry's edges with the yolk mixture, as well as the top and sides of the wrapped fillet. Unroll the fillet from the cling film and sit it in the centre of the smaller strip of pastry. Roll out the remainder of the pastry to about 28 x 36cm, also 2mm thick. Roll out a third of the pastry to an 18 x 30cm strip about 2mm thick and place on a non-stick baking sheet.
