I've had this pattern in for a while, Simplicity 2444.
My absolute favourite is by Yarning Over The Days and I love What I Wore and Stitchywitch, but of course there are loads more to choose from and plenty of variation in the pattern.
The muslin from a bed sheet, I might actually wear this though.
The only modification I think I'll need is to take it up on the shoulders so it sits above my hip bones,
I just pinned here.
Love the pockets.