850g fillet of beef
2tbsp. creamed horseradish
1tbsp. Dijon mustard
12 slices of unsmoked bacon
500g all butter puff pastry
For the mushroom layer
1tbsp. vegetable oil
15g unsalted butter
2 shallots, peeled and finely chopped
250g chestnut mushrooms, very finely chopped
1 garlic clove, finely chopped
1 sprig fresh thyme
100ml extra dry vermouth
150g smooth liver pate
Season the fillet well with salt and black pepper, add to a large vacuum bag and seal on the highest setting. Transfer into a Miele Steam Oven, select the Sous Vide setting and cook at 46ºC for two hours. When ready, remove from the bag, brush with some vegetable oil and sear all over using a large frying pan over a high heat. Allow to cool completely.
Wipe the frying pan and melt the oil and butter over a medium heat and cook the shallots for a few minutes until softened. Add in the finely chopped mushrooms (if possible, chop them using a food processor) along with the garlic and thyme and cook for a further five minutes. Pour in the wine and cook for a further ten minutes until all the wine is completely absorbed and the mixture is dry. Allow to cool for a couple of minutes, remove the sprig of thyme, and stir in the liver pate and the chopped parsley. Season to taste and then set aside to cool completely.
Overlap two pieces of cling film on a clean work surface and lay out the slices of bacon in two rows, slightly overlapping each other. Combine the creamed horseradish and mustard together and brush the beef all over with it. Spread half the mushroom mixture over the bacon, sit the beef on top and spread the remaining mushroom mixture over the top of the beef. Using the edge of the cling film, draw up the bacon around the beef fillet to create a tight sausage shape. Place in the fridge for a few minutes while rolling out the pastry.
Lightly flour the work surface and roll out the pastry to a square about 0.5cm thick and large enough to enclose the beef. Carefully remove the cling film from the beef and place it in the middle of the pastry. Brush the edges of the pastry with some of the beaten egg and fold it over the beef to enclose it.
Place the Beef Wellington onto a baking tray with the seam underneath. Brush the pastry again with the beaten egg and chill for at least 30 minutes or overnight.