One of my biggest pet peeves as a cake decorator is not being able to make "real" buttercream with palm sugar. My pastor's wife, Ebbye, told me how to make powdered sugar from granulated palm sugar or thot not, which is the same thing. All you do is take 1 cup granulated palm sugar and one teaspoon corn starch and run it through the vita mix or food processor. I have neither so I borrowed my neighbor's Vitamix and it worked great. You can try a coffee grinder on the finest setting, but I don't know how that would work. As you are processing the sugar be sure not to go too long or it will turn into a paste. I made royal icing with it last night and it worked great! Yeah!