Preheat the oven to 350 degrees. Spray a 9 inch cake pan with cooking spray.

In a medium bowl combine the flour, cocoa powder, baking powder, and salt.

Mix the butter and sugars together until the are well combined. Then add in the eggs one at a time, beating after each addition. Stir in the vanilla.

Add in half of the dry ingredients, then the milk, and the remaining dry ingredients. Stir well.

Slowly mix in the boiling water until the batter is thin. Stir in the chocolate chips.

Pour the batter into the prepared pan. Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.

Cool the cake for 5 minutes then run a knife around the edges of the pan. Invert the cake and cool for 20 minutes.

Turn the broil on high in your oven. Move the oven rack to 6-8 inches below the broiler.

Spread the mini marshmallows over top of the cake. Then sprinkle the broken graham cracker pieces on top.

Place in the oven, watching constantly, until the marshmallows become brown and toasted (but not too brown or they will catch on fire!)

Remove from oven and immediately press chocolate pieces into the marshmallow. Cook completely.