S'mores Cookie Bars

Preheat the oven to 350 °F. Grease the bottom and sides of a 9-inch by 9-inch square baking dish with butter. As the oven heats, mix the flour, crushed graham crackers, baking soda and salt in a mixing bowl. Set aside. Grab a larger mixing bowl and add in butter and sugars, beating on medium speed until the mixture is light and fluffy. Mix in eggs and vanilla, then reduce the mixer's speed to low and gradually add in the flour mixture, stirring just enough to combine. Pour half of the cookie dough into the baking dish, then top with a layer of chocolate, then spoon on the Marshmallow Fluff, using the back of a silicone spatula or a spoon to spread on an even layer. Roll out the remaining cookie dough and place it on top of the Marshmallow Fluff. Bake for 23-25 minutes, or until the cookie is lightly golden. Remove the bars, then turn the oven to broil. Sprinkle marshmallows and any remaining pieces of chocolate, then place in the broiler for 30 seconds, until the marshmallows are lightly toasted.