Preheat oven to 200ºC (180ºC fan-forced). Rub the beef with olive oil, sprinkle with dried mint and season. Place beef on a rack in a roasting dish. Add ¾ cup water to the dish. Roast beef for 40 minutes for rare, 50 minutes for medium and 60 minutes for well done. For ease and accuracy use a meat thermometer. Cover the roast with foil if overbrowning.
Remove beef, cover loosely with foil, and rest beef for 20 minutes before carving
Meanwhile, to make salsa verde, combine 2 tablespoons peanut oil, half the garlic, lime juice, lemon grass, chilli, mint leaves, coriander leaves and palm sugar in a small food processor. Blend until well combined. Set aside until required.
Heat the remaining peanut oil in a wok over medium heat. Add the garlic and stir-fry for 30 seconds. Add the mushrooms, Chinese broccoli and sugar snaps and stir-fry for a further 3 minutes, until the broccoli is just wilted. Remove from the heat, drizzle with sesame oil and toss to coat.
Serve beef with salsa verde, stir-fried vegetables, rice and lime wedges.
The salsa verde would be great with any cut of lamb as a sauce.
You could substitute any type of herb for the mint and coriander in the salsa verde – for a greek twist use oregano and parsley and serve with Greek salad.
Any leftover lamb could be used in a salad or wrap the next day.