Preheat oven to 425° F and line a baking sheet with parchment paper, set aside.

In a large bowl, whisk together the flour, ½ cup graham cracker crumbs, 1 tablespoon sugar, baking powder, salt and baking soda until well combined. Add in the cold butter and cut in using your hands or a pastry blender. Work quickly breaking up the butter until it resembles coarse crumbs in varying sizes. Make a well in the center and pour in the buttermilk. Using a spatula, mix until the mixture forms a shaggy dough. Turn out onto a clean, lightly floured, work surface and pat together into a 1-inch thick square.

Using a 3-inch round biscuit cutter, cut out as many biscuits as possible and transfer to the prepared baking sheet, spacing them about 1-inch apart. Rework the remaining dough once more and cut out the remaining biscuits. Chill in freezer for 10 minutes.

In a small bowl, stir together the remaining graham cracker crumbs and sugar. Brush the tops of the biscuits with the melted butter and sprinkle a teaspoon or so of the graham cracker sugar mixture on top of each. Reduce the oven temperature to 400°F and bake until golden brown, 18 to 20 minutes. Remove from oven and let cool slightly.

To assemble, preheat your broiler on low. Split open the biscuits, leaving the bottoms on the baking sheet and top each with a piece of chocolate. Place until the broiler for about 30 seconds or so or just until the chocolate has begun to melt. Skewer each marshmallow and toast with a kitchen torch or on your stove-top, if you have a gas burner. Top each with a toasted marshmallow and sandwich with the biscuit tops. Serve immediately and enjoy!