Preheat your oven to 350°F and prepare two baking sheets by lining them with parchment paper and lightly greasing them with cooking spray.

In a large bowl, mix together the powdered sugar, cocoa powder, and salt.

Add the egg whites and vanilla to the dry ingredients, then stir in the chocolate chips. For extra shiny cookies, let the dough rest at room temperature for 20 minutes.

Scoop out tablespoon-size portions of dough onto the prepared baking sheets and bake until set, which should take about 10 to 12 minutes.

Allow the cookies to cool on the baking sheet for about 5 minutes before carefully transferring them to a cooling rack using a spatula. Let them cool completely before serving.