In a stand mixer, blend together the Nutella, peanut butter, brown sugar, egg and vanilla about 1-2 minutes on medium speed. Slowly add in the cocoa powder and baking soda, mixing for another minute until well-blended.
Line a cookie sheet with parchment paper. Scoop ½ tablespoon dough balls onto the sheet, about 3 per row. Once all the dough is scooped, use a fork to push down the dough so it is about ½ inch thick and make criss cross marks in the cookies. Refrigerate for 1 hour to set.
After refrigerating, bake at 350°F for 8-10 minutes or until edges start to firm. Serve warm with a glass of milk and enjoy!