'Kvetching' is amusingly offensive

Yet this is not a case of smut for smut's sake: It's how she relates and charms, as a quintessential New Yorker (she loves her native city ''because everyone there is as hostile as I am"). In her mock-swanny opening number, delivered in a mink jacket and gold lame sheath, Hoffman immediately establishes her persona, that of embittered also-ran, by alluding to her descent from the Broadway hit ''Hairspray" to this gig ''slumming" in Boston. She's the anti-Julie Andrews: Her set could be retitled ''These are a few of my least favorite things."

Topping the list are children, and Hoffman presents a compelling -- if often outrageous -- case against them. Even fond parents are likely to be tickled by her barbs, and especially her variation on Stephen Sondheim's ''I'm Still Here," as rendered by a jaded child star. (''What's funny is that it's usually sung by an older woman," Hoffman condescendingly explains to a hapless onlooker seated at one of the cabaret tables in the front row.) She's a powerful singer, with just enough self-mockery to undercut her impressive vocal chops. (She's still miffed that she couldn't score an audition for ''Fiddler on the Roof." Rosie O'Donnell -- whom Hoffman impersonates brilliantly -- had better watch her back.)

Now that she has arrived (her trio of one-minute cameos in ''Hairspray" led to juicy roles in John Waters's ''A Dirty Shame" and other films, plus TV appearances on ''Curb Your Enthusiasm"), Hoffman is incensed by the expectation that successful actors donate their time to benefits. Never mind that, in appearing in this tiny theater on behalf of the Theatre Offensive, she's essentially doing just that. ''Nobody will benefit from this evening! Nobody who is sick will leave here with more hope," she says. ''But I'm going to get a check, and" -- directing her remarks to Theatre Offensive founder Abe Rybeck -- ''it better clear, you [expletive]!" (A warm, semi-apologetic smile usually follows her own forays on the offensive.)

If there's one moment that makes Hoffman's show a must-see -- and there are many -- it would be her quick-change impressions of Bernadette Peters and Mary Tyler Moore chairing a ''Broadway Barks" benefit to support the adoption of strays: ''Take a pet home," she intones, alternately pouching her cheeks and stretching them into a postsurgical mask.

Hoffman has been labeled a ''rubber face" so often, she jokes that ''instead of a face lift, I'm going to have a retread." Her self-deprecating remarks can't obscure the fact that she's one beautiful woman, vibrant and bold. And there's never any question that her viciousness is just an act. Sometimes you have to be cruel to be painfully funny.