Mix together the lamb, beef, shredded garlic, buttermilk, onion, dried spices, panko crumbs, eggs, parmesan, salt and pepper. Form into large balls, about 2-3"/5-8cm wide. Heat BBQ to medium heat. Place meatballs on the grill (recommended to use a grill mat). Cook for about 10 minutes, turning halfway through, or until the inside of the meatball is fully cooked. For sauce, place all the ingredients in a pot and place on the stove on medium heat. Bring to a simmer and reduce temperature to medium-low. Simmer for 20 minutes. If desired, blend sauce to make smooth. Place meatballs in pot with sauce, turning gently to fully coat and heat through if cooled. Place on plate, pour sauce over meatballs. Serve.