1. In a food procesor process all the Chermoula ingredients to a paste consitency.
2. Cut the lamb into large cubes and dice the potato and sweet potato into similar sized pieces.
3. Mix all ingredients together with the Chermoula paste and marinade for at least 4 hours or preferably overnight if possible.
4. Pre-heat the oven to 150oC.
5. Remove the marinated meat from the refrigerator and mix in 1 1/2 cups of water. Place mix in a Tagine or a heavy based large pot and close the lid.
6. Cook at 150oC for 3 hours, checking after 2 hours and adding a small amount of water if required.
7. Serve garnished with coriander leaves and blanched almonds, on couscous.