In 1938, Minnie returned to recording for the Vocalion label, this time accompanied by Charlie McCoy, Kansas Joe's brother, on mandolin. Around this time she married the guitarist and singer Ernest Lawlars, known as Little Son Joe. They began recording together in 1939, with Son adding a more rhythmic backing to Minnie's guitar. They recorded for Okeh Records in the 1940s and continued to record together through the decade. By 1941 Minnie had started playing electric guitar, and in May of that year she recorded her biggest hit, "Me and My Chauffeur Blues". A follow-up date produced two more blues standards, "Looking the World Over" and Lawlars's "Black Rat Swing" (issued under the name "Mr. Memphis Minnie"). In the 1940s Minnie and Lawlars continued to work at their "home club," Chicago's popular 708 Club, where they were often joined by Broonzy, Sunnyland Slim, or Snooky Pryor, and also played at many of the other better-known Chicago nightclubs. During the 1940s Minnie and Lawlars performed together and separately in the Chicago and Indiana areas. Minnie often played at "Blue Monday" parties at Ruby Lee Gatewood's, on Lake Street. The poet Langston Hughes, who saw her perform at the 230 Club on New Year's Eve, 1942, wrote of her "hard and strong voice" being made harder and stronger by amplification and described the sound of her electric guitar as "a musical version of electric welders plus a rolling mill."