In a medium sized mixing bowl whisk together the flours, cornstarch, baking powder, baking soda, and salt. Set aside.

In the bowl of a stand mixer combine the cold butter, dark brown sugar, and, regular sugar. Beat on medium speed until all three ingredients are well incorporated.

Add the eggs and vanilla and mix well.

Add the cocoa powder and mix well scraping down the sides of the bowl with a rubber spatula.

Next, using the paddle attachment, add the flour mixture to the wet ingredients. Mix until well combined.

Add the chocolate and peanut butter chips and mix until everything is well combined.

Scrape all dough into a gallon sized Ziploc bag (the dough will be very thick). Press dough around in the bag so it forms a flat, thick, even layer in the bag. Seal the bag and refrigerate dough overnight.

When you are ready to bake the cookies preheat your oven to 375° F and line a large cookie sheet with parchment paper or a SILPAT

Remove the dough from the fridge and cut the bag off of the outside of the dough.

Cut the dough into 16 equal squares.

Place on baking sheet and bake for

15 to 18 minutes.

Let cool for a couple of minutes. EAT!!!

These cookies are best warm. If you don't eat them all in one sitting (like me) then reheat them in the microwave for 5 to 10 seconds each before eating.

Adapted from the Levain Bakery Dark Chocolate Peanut Butter Chip Cookie Clone recipe at Fran's Faves