1 1/2 - 2 cups graham cracker crumbs about 14 full graham crackers
2 teaspoons baking powder
1/2 teaspoon salt
3 Giant Sized Hershey's Milk Chocolate Bars
16- oz. tub or 3 cups marshmallow fluff
Preheat oven to 350 degrees.
Lightly grease or spray with cooking spray a 9-inch x 13-inch glass baking pan and line it with parchment paper, so the paper hangs over the sides a little. Set pan aside.
In a separate bowl, whisk together the graham cracker crumbs, flour, baking powder, and salt and set aside.
Using a mixer, in a large bowl, mix together the softened butter, white sugar, and brown sugar for 1 1/2 to 2 minutes.
Add in the eggs and vanilla and continue mixing until well incorporated and smooth.
Add in the dry mixture into the butter / sugar mixture. Beat to incorporate, just until all the ingredients come together.
Gather the dough into a ball and divide dough into 2 balls.
Take one of the balls and spread out into the prepared pan by smooshing it down so that it covers the bottom of the pan completely in an even layer.
Cover the dough with a single layer of the chocolate bars. 3 fits nicely.
Next, add the marshmallow fluff to the top of the chocolate bars and spread out to sides of pan.
Lightly flour a board or counter top and smoosh or roll with a rolling pin, the other half of the s'mores cookie dough and make it/roll it the size of the your pan. I do it by placing the pan on top to get an idea about the size to get an idea. Slice the dough into strips and lay each piece on top of the fluff until you've covered it all as good as you can. Try to cover up all the marshmallow as good as you can, but it's ok to have some marshmallow poking out.
Place pan into your preheated oven and bake for about 30-35 minutes, until the top is golden brown.
After baked, transfer to cool completely on a rack.