Preheat oven to 350 degrees.
Line a baking sheet with parchment paper.
Mix icing sugar, 3 tablespoon cocoa powder and cornstarch on low until combined.
Add egg whites and beat on low until combined and then high for 1 minute. The batter will be shiny.
Stir in chocolate sprinkles and mini chocolate chips.
Remove ½ cup of batter and add the black cocoa powder to this mixture.
Add the ½ cup of batter with black cocoa in it back into the original batter. Pass a knife through the batter just a couple of times to swirl the two batters together. Only pass through the batter a couple of times to achieve the swirled pattern. Do not mix the batters together.
Drop by small spoonfuls onto the prepared baking sheet.
Bake for 12-15 minutes or until the tops begin to crack.
Move on the parchment paper to a cooling rack and let fully cool. They will peel off the parchment paper easily once cooled.
Store at room temperature.
