ENGAGED: Liza Minnelli, 55, to television producer David Gest. They met on the set of "Michael Jackson: 30th Anniversary Special" and the Gloved One will serve as one of Gest's best men at the wedding ceremony next March. "Everything I've been through was worth it to find David," said Minnelli. It'll be her fourth marriage, Gest's first . . . DIED: Pop singer MELANIE THORNTON, 34, in a plane crash near Zurich. Formerly of La Bouche, Thornton was promoting her album "Ready To Fly," and her single "Wonderful Dream" is the backing track for a new Coca-Cola commercial. JUAN HINOJOSA, 51, drummer of Los Fabulosos Cuatro and inductee to the Tejano Roots Hall of Fame, in a car accident outside Corpus Christi. NORMAN GRANZ, 83, a concert promoter and manager (most prominently of Ella Fitzgerald) who fought for racial integration at jazz concerts in the 40s and 50s . . . NAMED: An organic heirloom tomato, for TV chef Julia Child, 89, at TomatoFest in Carmel, Calif. "This tomato isn't for sissies," announced Fest founder Gary Ibsen. Julia Child seeds are available at $4.50 a pack . . . MARRIED: Mary Bono, 40, to Glenn Baxley, 33, a Wyoming businessman and former minor-league baseball player. Bono took over the congressional seat of her husband Sonny after he died in a skiing accident almost four years ago.