Next Saturday night at the Mahaiwe, writer-director Heather Fisch presents La Belle Epoque, a live theater show about three vaudeville performers from the 1920s. Part slapstick, part jazz, part dance, the show is back in Great Barrington where it originally began. WAMC’s Alan Chartock spoke with Heather Fisch, who says the show has been a long time in the making.