I may be wrong, but I don't think Burt wrote that song, "Slow." It's on Rumer's debut album; before that album debuted, she released a smaller work called "Rumer Sings Burt" which included "Alfie" and a new song he wrote for the new-show-in-the-works, "The Gift of the Magi." That song is "Some Lovers." But "Slow," along with "Aretha," and some others are, I believe, written either by Rumer herself or other collaborators. But please, someone correct me if I've got this wrong.
Dear Marcel and Steve, The song, "Slow" was written by Sarah Joyce, which is Rumer's given name. Rumer is her "stage" name, inspired by author Rumer Godden. Most of the songs on her cd were written/co-written by her, except, "Alfie", "Goodbye Girl" (David Gates) and "It Might Be You" (Theme from "Tootsie", written by David Grusin, Alan & Marilyn Bergman).