PreparationMake marinade: Rinse black beans and pat dry. Chop beans fine and in a bowl whisk together with remaining marinade ingredients and salt and pepper to taste. In a large sealable plastic bag combine lamb and marinade and seal bag, pressing out excess air. Marinate lamb, chilled, turning occasionally, 2 hours. Prepare grill and preheat oven to 400°F. Remove lamb from bag and discard marinade. Grill lamb on an oiled rack set 5 to 6 inches over glowing coals. turning, until browned all over, about 5 minutes. Transfer lamb, meat sides up, to a shallow baking pan and roast in middle of oven 10 minutes. In a dry heavy skillet toast sesame seeds over moderately high heat, stirring, until fragrant and golden. Sprinkle lamb with sesame seeds and roast 5 to 10 minutes more, or until a meat thermometer registers 130°F. for medium-rare. Transfer lamb to cutting board and let stand 10 minutes.
PreparationMake marinade: Rinse black beans and pat dry. Chop beans fine and in a bowl whisk together with remaining marinade ingredients and salt and pepper to taste. In a large sealable plastic bag combine lamb and marinade and seal bag, pressing out excess air. Marinate lamb, chilled, turning occasionally, 2 hours. Prepare grill and preheat oven to 400°F. Remove lamb from bag and discard marinade. Grill lamb on an oiled rack set 5 to 6 inches over glowing coals. turning, until browned all over, about 5 minutes. Transfer lamb, meat sides up, to a shallow baking pan and roast in middle of oven 10 minutes. In a dry heavy skillet toast sesame seeds over moderately high heat, stirring, until fragrant and golden. Sprinkle lamb with sesame seeds and roast 5 to 10 minutes more, or until a meat thermometer registers 130°F. for medium-rare. Transfer lamb to cutting board and let stand 10 minutes.