Make sure the lamb shoulder is at room temperature before you start. this is important as it will ensure a tender and juicy finished product. Remove it from the fridge at least 2 hours prior to cooking.
Peel and roughly chop the garlic, zest 2 of the lemons and roughly chop the bunch of oregano. Mix together.
Using a small knife, make several small incisions in the skin of the lamb. Stuff these with prepared mixture of lemon zest, galic and oregano. Rub any remaining marinade onto the underside of the lamb.
Pre heat a fan oven to 160 degrees Celcius.
In a large frying pan, pour in some olive oil and place on the hob on a medium heat. Season the lamb on both sides with salt and pepper. Place it carefully, skin side down, in the pan and allow to brown. This will take around 5 minutes. You are in control of the heat! If the meat is not browning, turn the heat up. If it is browning too much, turn the heat down. When you have achieved an amber colour, the lamb is ready for the oven.
Place the lamb directly on the middle oven shelf, skin side up, with a roasting tray on the shelf underneath. This will catch any juices and fat rendering from the lamb as it cooks. Do not throw these away! They will be used to cook the potatoes.
Cook at least 3 and a half hours.
Peel and cut he potatoes into thick wedges.
Cut the remaining 3 lemons in to wedges.
Cut the garlic bulbs in half, leaving the skin on.
Rip the rosemary into a few pieces.
Mix the above in a mixing bowl, ready to toss in the fat and juices of the lamb when enough have been gathered in the roasting tray. This will be after an hour or so.
Once the potatoes have been dressed, season with salt and pepper, place in a roasting tray and pop them in the oven under the lamb, to catch any more delicious juice rendered from the meat. Their cooking should begin around one and a half hours before the lamb is done.
Finally, pick and chop the remaining oregano and sprinkle over the potatoes once they are cooked. You should also sqeeze the juice of one of the zested lemons, used for the marinade. This will cut through the richness of the potatoes.
Place the whole lamb shoulder on a serving plate together with the potatoes and allow your guests to help themseves, feast, and enjoy!
«You can also cook the lamb for longer at a lower temperature, resulting in an extremely soft and suculent meat. As a guide: 150 degrees for 4.5 hours 125 degrees for 7 hours»