Where Amy Winehouse’s Back to Black: B-Sides is a collection heavy on the covers (she only wrote two songs on it), her 2008 collection Frank (B-Sides) is heavier on original compositions that didn’t make it onto her 2003 debut album Frank. It opens with a demo of “Take the Box” sounding a little less refined and produced than the finished version, but the vintage keyboards are more prominent and the minimal drum machine recalls Timmy Thomas’ 1970s recordings. A spare take of “I Heard Love Is Blind” follows with a coffeehouse intimacy — a jazzy guitar is her sole accompaniment here. A sublime take on George Gershwin’s “Someone to Watch Over Me” plays with a sultry, smoky lounge feel.