Place the lamb in a large shallow baking dish. Combine the olive oil, lemon juice, rosemary, garlic, salt, and pepper. Pour over the lamb, cover, and marinate overnight in the refrigerator, turning once or twice.
Just before serving, preheat the broiler or prepare a fire in the barbecue. Arrange the meat and vegetables on separate skewers. (The meat takes longer to cook than the vegetables do.)
Broil or grill, turning and brushing with the marinade every few minutes. The meat will be done in about 10 minutes, the vegetables in 5 to 6 minutes. Serve at once.
This traditional way to prepare lamb is simple and simply wonderful, especially if you can cook it outside on a grill. Serve on or off the skewers with rice, a green salad, and pita bread that has been oiled, sprinkled with garlic, and toasted on a grill or in a toaster oven.