1-First: preheat the oven to 240°C (465°F) or 220°C (425°F) fan-forced. Then, rub the lamb shoulder with 2 tbsp olive oil, 2 tsp salt, and 1 tsp black pepper for a flavorful base. Make 12 deep incisions in the lamb, being careful not to go all the way through.

2-Next: insert the sprigs of rosemary and garlic slivers into those incisions to lock in extra taste. Place the quartered onion, halved garlic head, and extra rosemary in a roasting pan, then set the lamb on top. Pour 1 cup of water around the lamb to keep it moist during cooking.

3-Now: cover the roasting pan with a lid or double layer of foil and reduce the oven temperature to 180°C (350°F) or 160°C (320°F) fan-forced. Slow roast it covered for 3 hours to achieve that tender texture. After that, remove the foil and check the liquid; add ¾ cup water if needed to prevent anything from burning.

4-Increase the oven temperature back to 220°C (425°F) and roast uncovered for 20 30 minutes until the skin is browned and crisp. To check if it’s done, pull the meat apart with forks it should be tender. Let the lamb rest covered with foil and tea towels for at least 20 minutes before serving.

5-For the gravy, remove most of the fat from the pan, leaving about 2 tbsp. Place the pan on medium-high heat, stir in 2 tbsp flour, and cook for 30 seconds. Gradually add 2 cups beef broth or a mix of 1 cup red wine plus 1 cup water, then mash the onions and garlic to release their juices.

6-Simmer the gravy for 1 2 minutes until it thickens, and season with salt and pepper to taste. Strain it and serve alongside the lamb for a complete meal. Preparation takes about 15 minutes, cooking is around 3 hours 30 minutes, and the total time is roughly 3 hours 45 minutes.