Preheat the oven to 350 degrees. In a large bowl, stir together the powdered sugar, cocoa powder, cornstarch, salt, and cayenne pepper until evenly combined.

Add the egg whites, whole egg, and vanilla extract to the powdered sugar mixture. Carefully stir the mixture until all of the powdered sugar has dissolved into the eggs and a very thick batter forms. It may seem like there is not enough moisture to stir in all the powdered sugar, but keep stirring and it will eventually melt in. The mixture will be very thick and stiff, so use a strong spoon. Add the chocolate chips and stir until incorporated.

Line two baking sheets with parchment paper. Spoon the batter, one heaping tablespoon at a time, onto the baking sheets. Be sure to leave a couple inches between each cookie because they will spread. (I suggest ten cookies per sheet.)

Bake one cookie sheet at a time for 14 minutes or until the cookies are puffed and cracked over the surface. Allow the cookies to cool before removing from the parchment.