Chop up the unsweetened chocolate and place it and the butter into your double boiler. Melt, stirring frequently, and set aside to cool.
In a separate bowl, combine flour, cocoa powder, baking soda, and salt. Set aside.
In a large mixing bowl, beat together the eggs, sugar, and vanilla until the mixture is lightened in color and slightly thickened. Add the cooled chocolate and mix until combined. Add the dry mixture, mix on low for 2 minutes. Mix in chocolate chips.
Wrap dough in plastic wrap and chill for at least two hours. The dough should be COLD. Roll into small balls and then coat in powdered sugar. Place on a parchment lined baking sheet about 2-3 inches apart.
Bake at 350 until the edges are slightly firm to the touch. The middles will look slightly underdone. In my oven, this took about 11 minutes. Your may take a few minutes less or more. Leave the cookies on the sheet for 2 minutes after removal from the oven, and then carefully transfer to cooling racks.