Bob and BS&B’s Fifth Beatle, Jack Greiner, mucked around in the deep Mississippi mud that is the sordid, rumored history of “Ode to Billie Joe” and sang the praises of its woefully under appreciated author Bobbie Gentry. For good measure, they added Orville Peck’s cover of “Fancy.” They also played two cuts from Delta Sweete. Her masterpiece. Yes, masterpiece.