It's not just the unique texture of her voice--deep and dark and glistening, like Spanish leather--that makes a cabaret performance by Julie Wilson an unforgettable experience. And it's not only the masterful technique with which she shifts between singing and speaking that makes familiar Broadway standards seem brand new in her renditions. What Wilson brings to a song is penetrating intelligence informed by ripe, deep-seated eroticism; while her studio recordings of Sondheim and Weill aren't entirely satisfying, as a live performer she's stunning. Her readings of classic theater tunes mine the lyrics for bracing, even disturbing insights; for Wilson and her audience, the singing of a song is a process of discovery in which very intimate thoughts and feelings are laid painfully, wonderfully bare. Yet while redefining her material in such personal terms, Wilson never distorts the original intent of the composer; and William Roy's piano accompaniment, elegant in the classic Broadway style, is the perfect chaser for Wilson's extra-dry vocals. In her first engagement here since she starred on Broadway in Legs Diamond (the show was a flop but she was nominated for a Tony), Wilson is expected to perform work by Harold Arlen and Cole Porter; she usually devotes each set to one composer, so call the club for details. Tuesday through next Friday, July 14, Gold Star Sardine Bar, 680 N. Lake Shore Dr.; 664-4215.