Sift together the flour, cocoa, salt, and baking powder; set aside. In a medium bowl, stir chocolate into melted butter until melted and smooth. Mix in the sugar, eggs and vanilla. Gradually blend in the sifted ingredients. Stir in the chocolate chips. Cover dough and chill for at least 2 hours or overnight. Or chill in freezer 1/2 hour.
Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets or line them with parchment paper. Roll the chilled dough into 1 inch balls and roll each ball in confectioners' sugar. Place cookies 2 inches apart onto the prepared cookie sheets.
Bake for 10 minutes in the preheated oven, until the tops are cracked. Let cool 5 minutes before removing from cookie sheets to cool on wire racks.