"The Rose Bar Sessions" have hosted intimate concerts by the big namelikes of Axl Rose, Slash and The Black Keys. Those gigs, orchestratedby the Gramercy Park Hotel, went down after midnight and turned the hotels swanky boite into a loud, mini version of CBGBs. But last night none otherthan Liza Minnelli crooned at 6:45pm for a crowd that included SandraBernhard and girlfriend Sarah Switzer, Mary Louise Parker (and hotboyfriend Charlie Mars), Alan Cumming, Chris Constable, Mr. Mickey,gossip guru Michael Musto, writer Rachel Hellerand Tony Danza (go figure!). Wearing her signature Chinois-style blackvelvet jacket and black pants, Minnelli sat on a director's chair andsang six songs like "He's a Tramp," many from her new CD "Confessions,"which she says was inspired by singing for her parents VincenteMinnelli and Judy Garland, in their living room. Minnelli was in achatty mood. At one point, she held up the "Confessions" CD whichfeatures a black and white photograph of the singing diva. "Have youever seen so much retouching?" she asked the crowd. "I look swell!Sometimes I try and trick myself into thinking I look like that, but Ido feel like that."