Substitute chard or kale and spinach if you don't have access to a West Indian market and can't access the calalloo leaves (taro leaves). This is a trademark of Trinidad where crab and callaloo is the national dish. Served with rice, or macaroni pie, coo-coo or a selection of local root vegetables. Trini’s have this iron rich soup at least once a week, usually on a Sunday. Can be made in advance and freezes well.