In a 5- or 6-quart slow cooker place onions and olives. Arrange lamb in cooker. Sprinkle with garlic, rosemary, salt, and pepper. Pour broth over all.
Cover and cook on low-heat setting for 11 to 12 hours or on high-heat setting for 5-1/2 to 6 hours. Using a slotted spoon, remove lamb, onions, and olives from cooking juices and arrange on a serving dish. Skim fat from cooking juices. If desired, strain juices; pass with meat. Garnish with parsley. Makes 4 to 6 servings.