How to Make It
Preheat oven to 500°F with racks in upper and lower thirds. Combine the graham cracker crumbs, melted butter, and salt in a bowl and stir to combine.
Brush one half of a 10-inch cast-iron skillet with half of the butter mixture. Use your hands to stretch the dough into a 10-inch round, then place in the skillet. Press gently to cover the bottom.
Place the marshmallow creme in a microwave safe bowl and heat until spreadable, about 10 seconds. Dip a knife or small offset spatula into hot water, then spread creme over the half of the dough that the butter is on, leaving a ½-inch border. Place the chocolate on top of the creme, then the almonds, and marshmallows. Fold the other half of the dough over top of the filling and pinch edge to seal.
Brush the remaining butter mixture over the top of the calzone. Place the skillet on the bottom rack and bake until crust is golden brown, transferring to top rack halfway through, 14 to 16 minutes. Let sit 20 minutes in the pan, then transfer to a cutting board and cut into wedges.