Cream together butter, sugars, egg, and vanilla. Set aside.
In another bowl, mix together flour, salt, baking powder and soda.
Fold the dry ingredients into the wet ingredients.
Stir in chocolate chips.
Divide dough in half.
Spray a casserole dish with cooking spray.
Spread half the dough on the bottom of the casserole dish.
Lay 6 Hershey Bars across the dough.
Pour on the mini marshmallows.
Flatten the other half of the dough and lay it on top of the marshmallow layer.
Bake at 350 until the top of the dough is lightly golden, about 45-55 minutes.
Let cool, cut into squares, and enjoy.
Notes
* To make this recipe gluten free, substitute an all purpose gluten free flour blend. We use Bob's Red Mill all purpose flour for this recipe and it comes out perfectly.**Check to be sure all your baking products are gluten free if needed.