Christmas beef Wellington

1. Season the meat on both sides. Heat 2 tbsp of the oil
in a large frying pan until sizzling, then sear the beef on all sides to seal in the juices. Cook for 1-2 minutes until well browned, then remove from the pan and refrigerate until completely cool.

2. Meanwhile, gently fry the onion and garlic in the remaining 1 tbsp of oil for 4-5 minutes until beginning to soften. Add the pancetta and the mushrooms, and cook for 10 minutes, until the liquid has evaporated and a paste starts to form. Add the crushed chestnuts and chopped herbs, and cook for a further 2 minutes, then remove from the heat.

3. Line a baking tray with clingfilm and tip the mushroom mixture onto it. Press it out into a flat layer, then cover with another sheet of clingfilm. Smooth it over with your hands, then refrigerate until cold.

4. Preheat the oven to 200°C, gas mark 6 and line a baking tray with baking parchment. Unroll the pastry onto a lightly floured surface and use a rolling pin to roll it a little thinner, so it is around 0.5cm thick. Carefully lay the meat in the centre of the rectangle to work out how much space it takes up, leaving extra room to allow for the mushroom layer. Cut a small rectangle of pastry off each corner so the remaining pastry looks like a cross (this stops any areas of pastry from overlapping).

5. Set the meat to one side and peel the top layer of clingfilm off the mushroom mixture. Place the beef fillet into the centre of the mushroom mixture and use the remaining clingfilm to help wrap the meat in an even layer of filling. Use your hands to squeeze everything together, then carefully unwrap the layer of clingfilm and place the log into the centre of the pastry.

6. Brush the edges of the pastry with beaten egg, then fold it around the filling. Pinch the edges together to seal, then place onto the lined baking tray.

7. Cover the top of the pastry with beaten egg and score gently with a sharp knife. Top with a sprig of rosemary and bake for 25-30 minutes for rare or until a deep golden brown colour. The pastry should be crisp all the way around. Allow to rest for 10 minutes, then slice using a serrated knife to serve.