I'm not entirely sure but I think it was first recorded on a Delaney Bramlett (without Bonnie) album, possibly his 1975 MGM album "Giving birth to a song" (and obviously some bits and pieces would have been changed for the "Time" version (hence her writing credit on the "Time" version) as it's unlikely Bekka would have taken part in the writing of it back then) but I don't know for certain if that's the Delaney album it's on though but I'm sure I did hear somewhere that Delaney had recorded this song originally back in the 70's on his own. Sorry I couldn't provide better info on this but hopefully we can find out for sure about this one way or the other soon.
John