Preheat oven to 350 degrees F. In a bowl, mix flour, sugar, baking powder and baking soda together with a wire whisk. Separate the mixture in half into two bowls.
Stir cocoa into one bowl and the graham cracker crumbs into the other. Add 1/2 cup milk, 1 egg, 1 teaspoon vanilla and 1/4 cup oil to the cocoa mixture and beat on medium until combined. Repeat adding the same ingredients to the graham cracker crumb flour mixture.
Prepare the graham cracker crumb topping. Add the brown sugar and crumbs in a small bowl and pour on the melted butter. Stir until combined.
Pour a little graham cracker cake batter into the bottom of your baking cups and then sprinkle the topping mixture lightly on the surface. Place a marshmallow half on top and then cover the marshmallow with the chocolate cake batter until it is about 3/4 full. Sprinkle with more topping mixture.
Bake cupcakes for about 15 minutes. Place a cookie sheet underneath when you bake just in case. Let cool.
Broil at 400°F 1 jumbo marshmallow per cupcake. You''ll need to watch these closely and check them often so they toast and don''t burn. Once they''re toasted set aside to cool.
Heat the butter and cream on the stove. Heat until just before it boils. Remove and pour over chocolate. Stir until completely melted and smooth.
Pour over cupcakes. Add a dollop of marshmallow cream and a toasted marshmallow. Serve immediately.