George Ezra writes simple, hooky songs in the tradition of ’60s folk and sings with a sand-and-honey voice inspired by Howlin’ Wolf. He's lyrically fired up by travel away from his native UK (from “Barcelona” to “Budapest”), and he’s well versed in the roots of modern music (witness the rockabilly guitar to “Listen to the Man”). “Cassy O’” is a bluegrass stomp, but like all of Ezra’s songs, it’s meticulously arranged so that instruments appear, contribute, and depart, leaving space for that voice to do its stuff.