Preheat oven to 400 degrees F. In a food processor, lightly pulse together all the dry ingredients. Add the butter, cut into very small pieces, and pulse several times until pea-sized lumps of butter are apparent. With the processor running, add the water and continue running until just before the dough comes together (about 15 seconds). Turn out the dough onto a floured work surface and form into a disc; cover tightly and refrigerate for at least 1 hour.
Filling: Melt the chocolate and butter on top of a double boiler until smooth. Stir in the remaining ingredients until uniform in color.
On a floured surface, roll out dough 1/8-inch thick and cut out circles with a 4-inch round cookie cutter. Combine egg and water and brush circles with egg wash. Spoon the peanut butter mixture in the center of each round. Fold circle over 1 side to form a crescent shape and seal the edges firmly using your fingers. Using a floured fork, press the edges of the empanadas.
Brush the empanadas with egg wash and immediately dust with confectioners' sugar using a flour sifter or a fine mesh strainer. Bake in a pre heated 400-degree F oven for 15 to 20 minutes or until golden brown.