With chocolate inside and out, these cookies are sure to be a hit.
To the basic cookie dough, add the cocoa powder, baking soda, and melted chocolate.
Form dough into a log on a sheet of plastic wrap and roll up (dough will be hard to slice and may crumble).
If desired, roll edges of each slice in finely ground salted, roasted pistachios and then in raw cane sugar (Demerara sugar) before baking.
Add a chocolate drizzle to dress these cookies up: Melt three and a half ounces of chocolate and allow to cool slightly. Transfer to a zip-top bag and snip off a corner. Pipe chocolate evenly over the cookies. Let chocolate set before storing the cookies.