Preheat the oven to 350 degrees Fahrenheit. Line a cookie sheet with parchment paper or a silicone liner.
Add the butter and sugars to the bowl of a stand mixer, or a large bowl with a hand mixer, and cream them together until light and fluffy. 1 cup unsalted butter, 1 cup brown sugar, 1/2 cup granulated sugar
Add in the eggs and vanilla extract and mix until just combined. 2 large eggs, 1 TBS vanilla extract
Add in the flour, cocoa powder, cornstarch, baking soda, and salt. Mix until you have a nice, and soft cookie dough. Scrape down the sides and bottom of the bowl as needed. 2.5 cups all purpose flour , 2/3 cup Special Dark cocoa powder, 1 TBS cornstarch , 1 tsp baking soda, 1 tsp salt
Scoop about 1/4 cup of cookie dough and roll it into a round ball (mine were each 70grams). Roll each ball into a small bowl of Oreo crumbs. 1/4 cup Oreo crumbs
Place 6 balls on each prepared baking sheet.
Gently press the top of the balls to flatten them slightly.
Bake the cookies for 9-13 minutes, or until the cookie tops start to crack and the centers look set.
Remove the pan from the oven, and let the cookies cool for 5 minutes on the pan.
Transfer to a wire rack to cool completely.