You will understand, then, why I was shocked to learn recently that New Zealanders consider pavlova their national dish, too. What's more, they claim to have invented it. In January, New Zealand's new national museum, Te Papa, announced it would celebrate its first birthday with a giant pavlova, named Pavzilla, which it then identified as ''a great Kiwi icon''. Shortly afterwards, the Sydney Morning Herald _called this assessment ''a delusion''. ''Those bloody Australians,'' spat back Sarah-Kate Lynch, food editor of the _New Zealand Herald. ''It's so typical. They're always trying to steal our best ideas.''