Here in Philly, we really like the sandwiches that we consider our own. The roast beef sandwich is certainly not that — it’s beloved the world over. But that doesn’t make it any less Philly ...

Roast for 23 minutes for medium-rare (only 20 minutes if it is a long, thin piece). When the beef is cooked, remove from the oven, cover with aluminium foil and leave to rest for 15 minutes.