Directions

1. 1. Season the meat with salt and pepper.
2. 2. Heat the butter or margarine and oil in a frying pan (skillet) and brown the meat quickly on all sides over a high heat, then turn down the heat to moderate and cook turning occasionally, for 10 minutes.
3. 3. Remote from the pan.
4. 4. Add the onion and mushrooms to the pan and fry (sauté) for 3 minutes until softened. Stir in the parsley and remove from the heat.
5. 5. Preheat the oven to 220°C/425°F/ gas mark 7. Rinse a baking (cookie) sheet with cold water.
6. 6. Roll out the pastry on a lightly floured surface to a square about 2.5 cm/1 in longer than the piece of meat.
7. 7. Spread the pate down the centre and top with the onion and mushroom mixture. Lay the meat on top.
8. 8. Brush the edges with water and fold the pastry up over the meat to cover completely and fold in the ends to form a parcel
9. 9. Place, folded-sides down, on the baking sheet and brush the top and sides with beaten egg. Make several small slashes in the top of the pastry.
10. 10. Bake in the oven for 15 minutes, turn down the heat to 190°C/375°F/ gas mark 5 and cook for a further 10 minutes.
11. 11. Meanwhile, cook the new potatoes, then the peas.
12. 12. Carefully transfer the beef to a warm serving dish.
13. 13. Garnish with parsley and serve cut into thick slices with the horseradish relish, potatoes and peas.