Wash lamb shanks and make big and deep gashes. This is very important if you want a flavorful spicy meat.
Mix all the ingredients except lamb to a paste.
Rub this spice paste on to the lamb and into the gashes. Use your fingers to rub the meat as deep as you can.
Take a baking dish and place a banana leaf in it. Place the lamb on the leaf and pour any remaining spice mixture over it.
Fold the banana leaf over the lamb to cover the lamb and it should look like a packet. Cover the baking dish and marinate in the refrigerate overnight or 24 – 48 hours.
Remove marinated lamb from the fridge and leave it on the countertop for 30 – 60 minutes before cooking, to bring it to room temperature. This is an optional.
Preheat the oven to 250F and place the baking dish in the oven. Do not forget to remove the cover/lid of the baking dish.
Bake lamb wrapped in banana leaf for 3 hours or until the meat is tender. Turn the meat around very 1 – 1 ½ hours.
It took 3 hours in my oven and the meat was tender. Depending on the size and thickness of the meat, one may have to cook it longer.
Change the oven temperature to 350 F, open the banana wrap and cook for another 20 minutes until the meat is dark brown.
After cooking for 3 hours, banana wrap will dry up and will begin to fall apart. I left the leaf in the dish itself and opened /removed the leaf on the top before roasting it at 350 F.
Remove from oven and let the meat rest for at least 10 minutes before serving.
I served it with flavored rice.