In a stand mixer bowl, add the cubed chopped butter and mix until butter is fluffed up.
Add in the sugars and beat again until fluffy, making sure to keep scraping the sides.
Add in the eggs and vanilla and mix again.
Sift and beat in the flour, cake flour, cocoa powder, baking soda, cornstarch and salt. Only for about 30 seconds.
Beat in the mix ins until it comes together.
Scoop about 6oz of the dough and shape it into a tall cone shape.
Refrigerate and chill for 4 hours.
Preheat oven to 410°F.
Place the cold cookie doughs on a lined baking sheet and bake for 9-11 minutes.
Remove from oven and let it cool.
