In a large bowl combine egg, onion, Parmesan cheese, the snipped fresh or the dried oregano and/or basil, the ketchup, garlic, salt, and pepper. Add ground beef and ground turkey; mix well. Shape mixture into eight 3/4-inch-thick patties.
For a charcoal grill, place patties on the rack of an uncovered grill directly over medium coals. Grill for 14 to 18 minutes or until no longer pink (165 degrees F), turning once halfway through grilling. Toast ciabatta rolls on the grill. (For a gas grill, preheat grill. Reduce to medium. Place patties, then ciabatta rolls on grill rack over heat. Cover and grill as above. )
Serve burgers on toasted ciabatta rolls with tomato slices and, if desired, additional fresh oregano and/or basil sprigs.