Serves 2

TO SERVE
1 Divide the spinach between two warmed plates and top each pile with a piece of fillet.
2 Add a large spoonful of potato to the dish, placing carefully next to the beef.
3 Spoon over a little of the herb dressing and serve.

• Mix the herbs together and put 2 tbsp aside. Sprinkle the remainder into a large bowl and stir in the salt, egg and water. Gradually add the flour, mixing with clean hands until a firm, elastic dough is formed. Cover with cling film and allow to rest for 15 minutes.
• Preheat the oven to 200°C/Gas 6. Season the beef all over with ground black pepper but not salt. Heat the oil in an ovenproof frying pan and fry the beef for 3-4 minutes, turning regularly until nicely browned on all sides. Transfer to a plate and roll in the reserved herbs until lightly coated; set aside.
• Roll out the dough on a lightly floured surface to form a circle roughly 28cm in diameter and around 5mm thick. Place the beef in the centre of the circle and cut through the dough - at right angles - from each corner of the fillet. Remove the excess dough – you should have four pieces - leaving the beef sitting in the centre of a wide cross shape.
• Bring the dough up and over the beef to fully enclose – pressing firmly with fingers to seal. Patch up any holes using the excess dough. Turn over, so most of the joins are on the underside, and place on a lightly oiled baking tray.

6 Transfer the beef parcel carefully to a chopping board. Cut open the crust with a sharp knife and discard. Pat the beef with kitchen paper to remove any excess salt. Cut into two portions.

1. Check the meat is cooked by inserting an electric temperature probe into the centre of the fillet – it should read around 55°C when the beef is cooked to rare. Increase the cooking time by 5 minutes for medium rare beef.
2. WARNING! DO NOT EAT THE SALT CRUST.

1. If you can’t find chervil, use 1 tbsp more chopped fresh parsley in its place.
2. This sauce will keep well for up to 24 hours in the fridge and goes brilliantly with all sorts of grilled or roasted meat and fish.

1. Choose potatoes of a similar size so they all cook at the same time.
2. Bake the potatoes on coarse sea salt or sea salt flakes to prevent them from sticking to the tray and to help ensure crispy skins. Test they are ready by inserting a skewer into the centre of a couple of potatoes – it should slide in easily.
3. You can eat the potato skins after baking if you like. Simply brush off the excess salt, drizzle with a little oil and return to the oven for a few minutes until golden. Serve warm with a soured cream and chive dip.
4. If you can’t get fresh horseradish root (try asking your greengrocer first – he or she may be able to order it for you), stir 1 tbsp grated horseradish from a jar or 3 tbsp creamed horseradish into the milk.
5. Use white pepper to season the potatoes as ground black pepper flecks will spoil the appearance of the mash.
6. For really smooth potatoes, pass through a clean, fine sieve one more time before serving.
7. If the potatoes become too cold to serve, simply warm in a saucepan with a little extra milk if necessary. Stir constantly as it is warmed.

• Push the garlic into the prongs of a fork and use to stir the spinach if you like.
• Do not allow the spinach to overcook and become soggy.