To prepare the marinade, purée the onion and garlic in a blender. Combine with Jordan Extra Virgin Olive Oil, thyme and black pepper in a shallow dish. Add the lamb, cover and let marinate in the refrigerator for 8 hours. Remove lamb one hour prior to grilling to bring to room temperature.
Grill lamb on medium high heat for 2-3 minutes per side, or to an internal temperature of 130 degrees for medium rare. Remove lamb from grill and allow to rest for 10-15 minutes.
Turn grill up to high heat and char the grapevine cuttings.
To prepare the sauce, combine grapevine cuttings, berry juice and garlic in a saucepan over medium heat. Reduce by half and add salt and sugar to taste. Strain sauce to remove grapevine cuttings. Discard cuttings.
To assemble, cut the lamb into bite size cubes. Arrange a silver or stainless steel pick beginning with a blackberry, then add an herb sprig and finish with a piece of lamb.
Serve grilled lamb skewers along with the sauce, topped with a dusting of thyme flowers, if available. Garnish plate with fresh berry leaves.