Preheat oven to 300 degrees F.  Line cookie/baking sheets with parchment paper or silicon baking mats. In a medium bowl combine flour, baking soda, salt, and cocoa powder.  Set aside. In a large bowl, cream brown sugar, granulated sugar and butter until light and fluffy.  Add eggs and vanilla.  Beat at medium speed until light and fluffy. On low speed, add the flour mixture and peanut butter chips to the butter mixture.  Blend until just combined.  Do not over mix, but make sure all ingredients are combined completely.

Using a #24 ice cream scoop (3 tbsp.) or a 1/4 cup measuring cup, scoop dough onto prepared baking sheets, 3 inches apart.  Bake for 23-27 minutes.   Remove from heat and allow baking sheets to cool completely on cooling racks.