El Dorado, Marcus King’s first solo album and fourth release overall, begins with the soft strums of an acoustic guitar before King croons a delicate vocal: “I left my home when I was 17/ My feet were dirty but my soul was clean/ I was looking for a young man’s dream, it seems.” Now 23, road-tested and, at times, sounding a bit road-weary, King is at his most tender on opener “Young Man’s Dream,” preparing the listener for the sonic shifts that are forthcoming. “The Well” follows with the familiar bluesy stomp of Dan Auerbach’s guitar. The Black Keys frontman leaves his fingerprints all over El Dorado , producing the LP at his Easy Eye Sound studio in Nashville, co-writing each song with King and playing on nearly every track. The album marks King’s third collaboration with a big-name producer: Gov’t Mule’s Warren Haynes helmed 2016’s The Marcus King Band and Dave Cobb (Sturgill Simpson, Chris Stapleton) oversaw 2018’s Carolina Confessions. Auerbach—along with a rotating roster of session musicians, in lieu of King’s eponymous touring band— may have had the biggest impact yet, giving El Dorado a sound more akin to the countrified, ‘70s soul of Auerbach’s two solo albums, 2009’s Keep It Hid and 2017’s Waiting on a Song , than King’s prior records. And though King delivers a ripping solo on “Say You Will,” El Dorado is the first of his albums to put the focus firmly on his voice, particularly “Beautiful Stranger,” “Wildflowers & Wine” and “Love Song,” a trio of seductive, countrified slow-burns. In many ways, this is his Willie Nelson album, something King winks at on the steel guitar-driven “Too Much Whiskey,” which namechecks “Whiskey River,” and “Shotgun Willie” before climaxing with a solo that would make Nelson himself proud.