Preheat oven to 350 degrees. Spray a 10 inch tart pan with non-stick cooking spray. Set aside.
Make brownie batter: In a small bowl, sift together flour, cocoa powder, salt and baking powder. Set aside.
In a medium bowl, cream butter and sugar together until fluffy. Add eggs, one at a time and vanilla and mix until well combined.
Slowly add the flour mixture and stir until just combined. Do not over mix. Pour the brownie batter into the prepared tart pan.
Make the peanut butter chocolate chip cookie dough: In a small bowl, whisk together the flour, baking soda and salt. Set aside.
In a medium bowl, cream together the butter, peanut butter, brown sugar and granulated sugar. Add the egg and the vanilla and continue to mix until well combined.
Slowly add the flour mixture and mix until just combined. Fold in the chocolate chips.
Place dollops of the cookie dough on top of the brownie batter.
Bake at 350 degrees for 25 minutes. Do not over bake. Remove from oven to wire rack to cool. When cool remove from tart pan to platter. Cut into wedges and serve.