Preheat oven to 350°F. Spray your 9x13-inch dish with cooking spray. Set aside.
In one bowl, combine the flour, Honey Maid graham cracker crumbs, 2. In a large bowl, whisk together the flour, graham cracker crumbs, dark brown sugar, baking powder, cinnamon, ginger, nutmeg, cloves and salt.
In another bowl, combine the oil, milk, eggs, vanilla extract and the pumpkin puree.
Mix together both bowls until well combined.
Spoon into prepared 9x13 baking dish.
Bake at 350°F for 35 minutes or a toothpick inserted in the center comes out clean.
Immediately upon removing from oven, layer the chocolate bars over the top of the baked cake and return the dish to the oven. (oven should be off) Leave in place approx. 2 minutes or until chocolate is melted.
Remove the cake from the oven and turn on the broiler.
Using a spatula, spread the melted chocolate over the entire cake as if icing the cake.
Layer the top of the melted chocolate with mini marshmallows.
Place the cake pan back in the oven under the broiler for about two minutes. Do not take your eyes off the oven, because the marshmallows will burn quickly.
You can turn the pan in the oven after the first 30+ seconds to "toast" the marshmallows more evenly.
Remove from oven and allow to cool for awhile.
Can be served cold or warm (warm is delicious!)