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°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. Makes 8 servings.