Ingredients

2 tbsp olive oil
1.5kg Coop British boneless beef roasting joint
4 tbsp English mustard
15g local unsalted butter
2 x 200g packs chestnut mushrooms, finely chopped
2 cloves garlic, peeled and crushed
Sprig fresh thyme (or 1 tbsp dried)
500g puff pastry
6 slices prosciutto
1 egg, beaten

Method

1. Preheat the oven to 200ºC/fan 180ºC/Gas 6

2. Lightly oil a baking tray

3. Rub half the oil over the beef joint and sear in a heavy based frying pan, over a medium heat for 5 mins

4. Remove from the pan and brush over the mustard

5. Heat the remaining oil and butter in the pan and gently cook the mushrooms with the garlic and thyme for about 5 mins

6. Roll the pastry out to a rectangle a few centimetres longer than the beef joint, and wide enough to fold over the joint, to encase it

7. Arrange the slices of prosciutto across the pastry, then sit the beef in the middle of it. Spoon the cooked mushrooms over the beef

8. Bring the proscuitto and pastry up and over the beef, then seal it and trim the ends

9. Score the top, then brush with the beaten egg and place on the oiled baking tray

10. Cook for 1 hour, until golden

Tips

The beef should be slightly pink inside