- For the Roast: Preheat the oven to 200°C. Place a rack in the centre of the oven and a lined roasting tray underneath.
- Add all marinade ingredients to a small blender and blend until chunky.
- Season lamb with salt and pepper then pour marinade over lamb. Place the lamb on the hot bars in the oven above the tray. Roast for 45 minutes then add potatoes.
- For the Mint Sauce: Pour boiling water over the mint and leave it to steep for a few minutes before draining through a sieve (this will increase the flavour), then rinse the mint under cold water (to stop it cooking). In a small bowl stir sugar into vinegar, then stir in mint. Add a pinch of salt and leave to infuse.
- In a large bowl toss potatoes with oil and salt and pepper. Carefully add to the hot roasting tray with rosemary sprigs and bake for 30-35 minutes, until golden and cooked.
- Cook the lamb for a total of 75 minutes if you want it pink, or 90 minutes for more well done.
- Remove lamb from the oven and let rest for 15 minutes before carving. Serve lamb with golden roast potatoes, mint sauce and steamed peas(optional).
Tip: Allow the lamb to come up to room temperature before you cook it