I make the "meatballs" for this dish from leftover hamburgers from my "Recipe#227860". I also use the leftover grilled onion slices from that recipe. This is like grilling once to dine twice. It's a smart way to use the grill, and an easy way to enjoy two deliciously different meals. These two perfect partners - beef and onions - are grilled once, but twice the amount you need for one meal. Enjoy half one night and save the other half for another night during the week. However, feel free to use your own version of meatballs for this recipe or your own leftover grilled hamburgers.