Fast-roast teriyaki lamb

I like this recipe because it’s a foolproof way of getting meat perfectly rare for a tableful of guests. Just make a timetable and stick it on the fridge door. Turn the oven on half an hour before your guests are due to arrive. When the last guest arrives, put the lamb in the oven before opening the front door. Join the guests for a drink. Half an hour later, take the lamb out, and set aside to rest. Serve the first course. When the first course is over, serve the lamb. No need to make grav