In a medium bowl, whisk together the flour, cocoa, baking powder and salt.
Using an electric mixer, beat the butter and brown sugar. Beat in the eggs and vanilla, then the cooled chocolate.
Reduce the mixer speed to low and gradually add the flour mixture, mixing just until incorporated.
Place the confectioners' sugar in a small bowl. Drop a slightly heaping tablespoon of dough into the confectioners' sugar and roll to coat and form into a ball; repeat with remaining dough.
Place the dough balls on plate or baking sheet lined with parchment paper and refrigerate for 30 minutes and up to 4 days.
Heat oven to 350 degrees. Lightly toss the chilled cookie dough balls in confectioners' sugar and arrange on baking sheets 2 inches apart. Bake for 8 minutes, rotating the position of the pans halfway through, until cookies are puffed, cracked and set around the edges.
Let cool about 3 minutes before transferring to a wire rack to cool completely.
Recipe by Let's Be Yummy at http://letsbeyummy.com/2013/12/18/crinkle-cookies-gluten-free-recipe/