Preheat the oven to 220°C.
Add the olive oil, lemon juice, oregano, cinnamon, mint and bay leaves to a large bowl and mix together. Season with salt and pepper to taste.
Place the lamb shanks into the bowl and rub with the mix.
Transfer the two lamb shanks to your cast iron casserole dish before adding the potato wedges and onion to the mixing bowl. Coat in the mix and place in the casserole dish.
Add the tomatoes and 200ml of water to the casserole dish.
Cover with foil, place the lid on the dish and place in the oven.
Lower temperatute to 160°C and cook for 4 hours, checking every hour. If the lamb is browning too much, turn it over in the dish.
Remove the lid from the dish and cook uncovered for 15 minutes to allow the meat to brown slightly.
Remove from the oven, replace the lid and allow to rest for 10 minutes before serving.