You have to chill the dough otherwise it is too sticky to roll into balls. I have ended up with chocolte dough covered hands because I was too eager to wait for the dough to chill enough. When in doubt, just make the dough the night before and let it chill overnight.
You then roll the balls in powdered sugar.
When the cookies bake, they melt from ball form into the typical cookie shape. This makes the powdered sugar split and crack like in the photo above.
As long as you don't overcook them, you're in for a world of yummy chocolaty goodness. Just be careful with the powdered sugar when you're eating them. I always find a trail of powdered sugar and crumbs when I try to eat them and walk around the house.
