Cut the sweet potato into bit size pieces, then mix with cumin, black pepper and salt. Roast at 200 C (400 F). Rub lamb with coriander, paprika, oregano, tomato paste, cinnamon, black pepper, salt and dash of sugar. Set aside and pre-heat the grill. Sauté green beans with garlic and onions, add black pepper, then add chicken stock and reduce to a simmer and cover. Grill lamb to perfection and serve. The sweet potatoes are the slowest as they take about 30 min in the oven.