Preheat the oven to 350 degrees. Line a couple baking sheets with parchment and set aside.
In the bowl of a stand mixer, combine the softened butter, brown sugar and sugar. Cream for about 2 minutes, until combined and smooth.
Add in the vanilla, eggs and corn syrup. Mix well.
Add in the cocoa, flour, baking soda, corn starch and salt. Mix thoroughly, scraping down the sides often.
Fold in the chocolate chips until evenly distributed.
Using a large ice cream scoop, divide the dough between the prepared baking sheets.