Preheat oven to 350°F. Grease a 9x13 baking pan; set aside. In a small bowl whisk together the flour, baking soda and salt; set aside.

In the bowl of an electric mixer, cream together brown sugar, peanut butter, butter and sugar on medium speed until creamy and light. Add egg and vanilla and mix until combined. Reduce speed to low and add dry ingredients, mixing only until the flour is just incorporated. Using a rubber spatula, mix in chocolate chips and peanut butter chips.

Turn out the mixture into the prepared pan and press into an even layer. Bake 16-20 minutes, or until the center is set. Cool completely in the pan on a wire rack. Cut into bars and store at room temperature in an airtight container.