For a slow roasted shoulder that falls off the bone, use a sharp chef’s knife to make 6-9 small but deep cuts in the lamb, through to the bone. Sit in a shallow-sided baking dish. Massage oil and seasoning into the cuts. Cover loosely with foil. Roast in the preheated oven for 2½-3 hours (or until the meat begins to fall from the bone), removing the foil in the last 30 minutes of cooking time. Remove from the oven and allow to sit covered for 20 minutes, reserving the juices. Carve the lamb into chunky pieces, place on a serving plate with your choice sides and drizzle over the reserved juices.
Season the lamb shoulder with salt and pepper and brown all over in a large frypan. Transfer to your slowcooker. Add browned, cut up vegetables for flavour and a small amount of liquid or stock. Cook as per slow cooker recipe / instructions.