Serves four to six
1 tsp black peppercorns
1 tbsp English mustard powder
2 tsp sea salt flakes
1.5kg (3lb) French trimmed rib of beef on the bone, tied with string
2 tbsp olive oil
2 onions, quartered with root intact
2 large carrots, halved lengthways
675g (1½lb) potatoes, halved or quartered
1 garlic bulb, broken into cloves (not peeled)
Small handful soft thyme leaves
2 tsp plain flour
400ml (14fl oz) chicken or beef stock
Sea salt and freshly ground black pepper
Creamed horseradish, to serve
Preheat the oven to 230°C (450°F/gas mark 8).Heat a small frying pan and toast the peppercorns until aromatic, then place in a pestle and mortar and grind until cracked. Mix in the mustard and salt. Wipe the meat with damp kitchen paper and rub with the mustard mixture.Pour the olive oil into a roasting tin and add the onions, carrots, potatoes, garlic and thyme, tossing to coat. Season to taste, then push the veg to the edges and sit the beef in the middle of the vegetables. Roast for 15 minutes and then reduce the oven temperature to 200°C (400°F/gas mark 6) and roast for 10 minutes per 450g (1lb) for rare, 12 minutes for medium-rare and 20 to 25 minutes for well done.Take out and baste halfway through the cooking time and quickly turn over the roast potatoes.Remove the beef, onions and carrots from the tin and place on a platter. Cover with tin foil and leave to rest for 15 minutes before carving. Pop the potatoes and garlic into another roasting tin and continue to cook in the oven, removing the garlic cloves if they are starting to catch and burn.To make the gravy, pour the juices from the roasting tin into a jug and leave the fat to settle on top, then skim off the fat and discard, reserving the juices. Stir the flour into the roasting tin, scraping the bottom of the tin with a wooden spoon to remove any residue, then gradually stir in the stock and reserved juices. Place the tin directly on the hob and simmer for 5 minutes, stirring. Pour through a sieve into a gravy boat.To serve, carve the rested beef into slices and arrange on warmed serving plates along with the roast potatoes and vegetables