Step 1

Season the steaks with salt and sear in a hot pan with a splash of olive oil until brown all over, then remove season with pepper and allow to cool

Step 2

Add the mushrooms to a blender with the chopped garlic, shallots and tear off the thyme leaves, add some seasoning and blend until very fine, put into a dry pan over a moderate heat and cook until no more water comes out of the mushrooms and they appear dry, then spread on a tray to dry out further and cool

Step 3

Brush the steaks on both sides with the mustard and place in the centre of the pastry on top of the mushrooms and spread another spoonful of mushroom mix on top

Step 4

Brush the edges of the pastry with the beaten egg then fold the edges of the pastry over the fillet and seal the ends tightly trimming away any excess pastry, flip the wellington over so the pastry seam is at the bottom and place in the fridge to rest for at least 5 mins

Step 5

To cook preheat the oven to 220c with a lined baking tray inside, remove the wellington from the fridge and brush all over with egg wash and sprinkle with a little salt then place straight onto the tray in the oven (this will help to cook the underside of the wellington)

Step 6

Bake for 20-25 mins or until the pastry is golden and crisp

Step 7

Remove from the oven and rest for a few minutes – serve with blanched green beans or garnish with watercress