Place the unsweetened chocolate (1st chocolate) and butter in the top of a double boiler places over (not touching) barely simmering water. Heat, stirring often, until the butter and chocolate melt. Remove from over the water and set aside to cool slightly. In a bowl, stir together the flour, cocoa powder, baking powder, and salt. Set aside.
In a large bowl of an electric mixer fitted with the paddle attachment, combine the eggs, granulated sugar and vanilla. Beat on medium speed until light in color and thick, about 3 minutes. Beat in the melted chocolate mixture on low speed until blended. Add the dry ingredients and beat until incorporated. Mix in the chocolate chips.
Cover the bowl with plastic wrap and refrigerate until the dough is firm enough to roll into balls, about 2 hours.
Position a rack in the middle of the oven, and preheat to 325F. Line 2 baking sheets with parchment paper. Sift the confectioners’ sugar into a small bowl.
To form each cookie, roll a rounded tablespoon of dough between your palms into a 1 1/2-inch ball, and roll the ball in the confectioners’ sugar. Place the cookies 3 inches apart on the prepared baking sheets. Make sure to set them firmly onto the baking sheet so they stay firmly in place.
Bake the cookies, until the tops are puffed and crinkled and feel firm when lightly touched, 13-17 minutes. Le the cookies cool on the baking sheet for 5 minutes, then transfer the cookies to wire racks to cool completely. Store in an airtight container at room temperature for up to 3 days.