In a bowl, whisk together the powdered sugar, brown sugar, cocoa powder, salt and baking powder. Set aside.
In a microwave safe bowl, heat the chocolate chips for 30-40 seconds at a time until melted. Set aside to cool slightly.
Crack eggs and separate the whites from the yolks. Whisk the yolks until creamy and beat the whites until you have peaks.
Slowly mix the cocoa powder mixture into the egg whites.
Add the egg yolks, followed by the melted chocolate chips into your batter. Stir together until you have a creamy consistency. Cover and refrigerate for at least 4 hours.
When you are ready to bake, preheat your oven to 340 degrees F.
Form small balls with the batter and roll them in the additional powdered sugar. (Do this as quickly as possible, so your hands don’t melt the chocolate too much before baking).
Bake for approximately 10-12 minutes.
Remove and let cool on the baking sheet.