In a mixing bowl place the butter and beat with an electric mixer until the butter is smooth. Add the peanut butter and the sugar and continue to beat until smooth. Add the remaining ingredients and continue to beat until all of the flour is incorporated and the batter is smooth. Spray a large rimmed cookie sheet with cooking spray and pour batter into the pan. Spread the batter out into the pan and sprinkle the chocolate chips on the top of the batter. Bake the brownie at 350 degrees for 29-32 minutes, or until the center is not longer wet. Let bars cool and then cut into squares.