Preheat the oven to 350 and line a baking sheet with a silicone mat or parchment paper.
In a medium-size bowl, using an electric mixer on high speed beat the egg whites and vanilla until soft peaks form.
In a separate bowl, whisk together the powdered sugar, cocoa powder and salt. Ensure the mixture is free of lumps.
Add half of the dry ingredients to the egg white mixture and fold until no streaks remain. Fold in the remaining dry ingredients, and finally stir in the chocolate chips.
Scoop 8-10 equally sized portions of the batter onto the prepared baking sheet (I used a tablespoon cookie scoop and got 8 cookies).
Bake the cookies for 15-17 minutes. The surface of the cookies will appear dry and they will start to crack around the edges.
Let cool on the baking sheet for a few minutes before moving to a cooling rack.