1. Make small incisions and stuff your lamb shoulder with rosemary and garlic.
Then rub with olive oil and salt.
(doesn't affect the tenderness but adds plenty of flavour)
2. Pre-heat the oven as hot as it will go (~240 degrees).
3. Cover your lamb in foil or place it in a crock pot.
4. Turn the temp down to 180 degrees and slow-roast for 2 hours.
5. After you remove it from the oven, let it rest for 20 mins so it relaxes and separates from the bone.
Follow these steps and your lamb shoulder will fall off the bone, just like at your favourite restaurant.