Peanut Butter S'mores Bars

Preheat the oven to 350°F (175°C). Spray an 8x8-inch metal baking pan with nonstick spray and line with parchment paper, leaving overhang on the sides for easy removal. Arrange the graham crackers in a single layer across the bottom of the prepared pan, breaking pieces as needed to fully cover the base. In a medium bowl, whisk together the flour, baking soda, and salt. Set aside. In a large mixing bowl, beat the butter and peanut butter until smooth and creamy. Add the granulated sugar and brown sugar and beat for 2–3 minutes until light and fluffy. Add the eggs and vanilla extract and mix until fully combined. Add the dry ingredients and mix just until incorporated. Fold in the chopped peanut butter cups. Pour about 1/2 of the batter into the prepared pan and spread to the edges. Add a layer of chocolate chips then a layer marshmallow fluff on top. Spread and/or dollop the rest of the batter on top. You can place some more chocolate chips or chopped chocolate on top if desired. Bake for 30–35 minutes, or until lightly golden and mostly set in the center. Let cool before lifting the paper from the pan and slicing.