Actor, TV host, author, designer and producer Isaac Mizrahi is firmly ensconced in the pop-culture zeitgeist. Whether appearing as a judge on “Project Runway All Stars” or hosting his own talk show, Mizrahi has made an indelible mark on the entertainment and fashion industries. But did you know that he can sing? Like, really sing? At Spruce Peak Performing Arts Center in Stowe, the Hollywood polymath flaunts his chops with a performance the New York Times says is “determined to challenge the cultural status quo.” The one-of-a-kind, boundary-blending show marries comedy, commentary and classic songs in a Liza Minnelli-worthy cabaret.