Notes: I've had my sweet potato starch for a long time (lost in the back of my deep freezer), and I cannot seem to locate an available source for it now. I will keep looking for a source and will update this post when I find one. You can also use an equal amount of Tapioca Starch or Arrowroot.
You can also make this in a regular blender, it just might be a tad bit gritty. I do not recommend making this in a food processor, the sugar never "powdered" for me.