Preheat the oven to 350 degrees and prepare a baking sheet with parchment paper.
Divide out 4 oz of chocolate and roughly chop the it.
In a large bowl, whisk powdered sugar, cocoa powder and salt.
Add egg whites and egg. Whisk batter until it is smooth and glossy.
Fold in chopped chocolate and cocoa nibs.
Using a small cookie scoop, place batter on parchment prepared baking sheets at least 2" apart.
Bake for 14-16 minutes.
Cool on baking sheet.
Once the cookies are cool, melt the remaining 3 oz of chocolate.
Place into a piping bag and cut a small hole at the end.
Drizzle chocolate over cookies.