Preheat oven to 350

Line a 13x9" pan with parchment paper

In a bowl, combine the graham crumbs, flour, salt and baking powder set aside

Using a mixer, beat the butter and sugar until fluffy, add eggs and mix well

Gently mix the dry and wet mixtures together.

Press 1/2 of the dough into the prepared pan

Top with chips and marshmallow

Drop remaining batter over top, its ok if some marshmallow and chocolate show through

Bake in preheated oven for 30 minutes.

Allow to cool at least 30 minutes for easier slicing.