Preheat your oven to 350 and spray your baking dish with non-stick spray.
Combine your crushed graham crackers, sugar, melted butter and 1 tablespoon of peanut butter.
Mix well and gently press the mixture evenly into the bottom of your baking dish forming the crust.
Next evenly spread your mini marshmallows on top of the crust followed by the chocolate and peanut butter chips.
Bake for 10-12 minutes. The top will start to turn golden brown. If desired after 10 minutes, turn the broiler on low and ‘brown’ the marshmallows for a few minutes.
Let the S’mores bars cool completely before cutting into 16 squares.