Seal the duck breast fat side first in a hot pan with no oil until golden brown. Remove from the pan and allow to sit. Meanwhile, boil the sweet potato for 10 minutes until cooked and remove the water. Add the butter, salt and pepper to taste. For the savour, shallow fry the onions and garlic in a little butter then add liver and cook for about 2 minutes. Add the chopped prunes and mix well .For the sauce, add the orange juice to a hot pan and reduce by half. Add the chicken stock and reduce by one third. Finally add enough honey, cream and butter till you achieve the correct consistency. Meanwhile, continue to cook the duck breast in the oven for a further 10 minutes at 180`c.(medium to well ). While duck is cooking heat the sweet potato and sauce and serve with the cooked duck breast.