Make peanut butter cookie dough. In a large mixing bowl, Cream the butter and sugars with an electric mixer or by hand. Add peanut butter egg and mix thoroughly. Add dry ingredients and mix until fully combine. Cover mixture with plastic wrap and set aside while you prepare the batter mixture.
Pre-heat oven to 350 Degrees F. Line a 9x13 pan with aluminium foil or parchment paper. Set Aside.
Make Brownie Batter. Bring water to boil in a medium saucepan. After it begins to boil turn off heat. whisk in cocoa powder and unsweetened chocolate and whisk until it had fully melted. Next whisk in the butter and oil. Add eggs, yolks and vanilla and whisk until the mixture is smooth. Gently whisk in sugar then flour and salt. Do not overmix batter.
Transfer batter to prepared pan; spread batter into corners of pan and smooth surface. Scoop peanut butter cookie dough batter onto the brownie batter.
Bake for 30-40 minutes or until a toothpick inserted comes clean. Allow to cool for at least 10-15 minutes before attempting to cut. Cut into 36 brownies by cutting 4 lines lengthwise and 9 lines across.