Rub the lamb with olive oil, sea salt and freshly ground black pepper.
Using a small sharp knife, make small incisions all over the lamb and push rosemary leaves and some quartered cloves of garlic into each incision.
Heat a large skillet/pan over medium heat, add olive oil. Once hot, place shoulder of lamb in pan and seal each side, trying to get a nice golden colour. This should only take a few minutes, then remove from heat.
Take a large roasting tray and add the onions, carrots, celery, garlic and herbs to the tray, making a bed for your lamb to sit on.
Drizzle with olive oil, salt and pepper.
Add a half bottle of red wine, tomato puree and approx 1 cup of water.
Place the shoulder of lamb on top of vegetables and pour any resting juices into roasting tray.
Cover the tray tightly with 2 layers of foil and place into the oven.
Cook for 5-6 hours.
Remove from oven and place lamb shoulder on a platter, covering with foil again to keep warm.
Add the flour to juices in roasting tray, stir and bring to the boil.
Strain the gravy through a very fine sieve into a clean pan, bring it back to the boil and season or add more flour for thicker gravy if required.
Serve with roasted vegetables.
Recipe by Places We Go at https://placeswego.com/slow-cooked-lamb-shoulder/