I have to go with Tartan's method, it wastes a little fabric(use later in a scrappy) but you get a perfect wonky block every time. If you want a double border, just add another row of fabric and lay a bigger square on there wonky or not.
If you want to do it the other way Marguerita has a video showing how to do it :
http://www.youtube.com/watch?v=Uz90AMsLWyY