To earn this, you simply need to reach the platform you first see the Blue Egg thief from in Town Square
. Head up the staircase to the right of him and climb to the very top platform. From here, you're going to want to jump then glide around the wall and try and land on the platform. It can take a few tries to make it but the best way is to hit glide at the peak of your jump!
Here is a video guide on how I did it: