As it's on the bone, the meat stays juicy - cooked for four hours, the meat falls off the bone easily. The recipe for this is in the Jamie at Home cookbook, however it's very easy.
Slash the fat side of the joint with a sharp knife, cutting through to the meat. Rub the shoulder with olive oil, salt and pepper, getting it in the slash marks too.Get a load of garlic cloves and rosemary and put half of it in the bottom of the baking tray. Put the joint in and then put the rest of the garlic and rosemary on top of it. Cover it tightly with foil - this is important to keep the joint protected from the strong heat of the oven.
Leave it for four hours. Seriously, don't touch it.
Then get it out of the oven, keep the foil on and put a tea towel over it, let it rest for 10 minutes. Put it on a big plate and let everyone - or just you and your dining partner - rip into it.
Mr Oliver suggests serving it with smashed up veggies, but just have whatever you fancy or whatever is in season. My one recommendation having now made this twice is to get the joint from your local butcher. It is more expensive but far superior to the joint I bought in Tesco yesterday (even if The Scouser and I gobbled it up!)