Heat the oil in a large pan. Add the lamb shoulder and brown on all sides.
1 tablespoon olive oil, 1.3 kg lamb shoulder
Put the onions and carrots in the slow cooker. Place the browned lamb on top of the vegetables.
1 onion, 1 carrot
Using a sharp knife, cut holes into the lamb. Push a slice of garlic and some rosemary leaves into each hole.
2 g fresh rosemary, 3 garlic cloves
Season and pour on the stock. Be careful to pour the stock around the lamb, not over the top of it.
350 ml vegetable stock
Cook on high for 5 hours.
Remove the meat from the slow cooker and allow to rest for 30 minutes.
If you want to add even more flavour to the gravy, then once you have taken the seared lamb out of the pan, you can de-glaze it with either some stock of a glug of red wine. Once added to the pan, use a wooden spoon to scrape it and then pour it in to the slow cooker.
If you have any gravy left over, you can wait for it to cool and then pour it into freezer bags, lay flat and freeze.
The key to making this lamb really special is cutting the holes in it and stuffing them with garlic and rosemary.
Make sure you pour the stock in to the side of the lamb, as you don't want to knock the rosemary and garlic out of the lamb.
If you want to add some more flavour, and make it extra crispy on the outside, then after it has finished cooking in the slow cooker, transfer it to a roasting tin and cook it in the oven for 25-30 minutes.