Writer Geraldine Brooks, who grew up in Australia and is now a Vineyarder, gave the keynote address at the Australia Day Boston Dinner at Hotel Commonwealth on Tuesday night. The evening’s feast included Australian lamb and baked barramundi, as well as wine from Torbreck Vintners. The night raised money for the American Australian Association’s Education Fund, which supports fellowships in Australia and the United States. Brooks, whose latest release is “The Secret Chord,’’ was joined at the celebration by her son, Nathaniel Horwitz.