Refrigerate the mixture for 2 hours. Scoop 1 tbsp. balls of the chocolate mixture onto a wax paper lined baking sheet or large flat plate. Place in the freezer for 20-30 minutes, or until firm enough to roll in balls. (SEE NOTES)
While the truffles are chilling, combine the cocoa powder and powdered sugar and mix well. Remove the truffles from the freezer and roll into balls.