Smores Cupcakes

Name: Smores Cupcakes
Ingredients: * 1 cup all purpose flour; * 1 cup sugar; * 1/3 cup unsweetened natural cocoa powder; * 1 teaspoon baking soda; * 1/2 teaspoon baking powder; * 1/4 teaspoon salt; * 1/2 cup buttermilk; * 2 large egg, lightly beaten; * 1/4 cup vegetable oil; * 1/2 cup hot coffee; for frosting; * 1 1/2 cup (3 stick) unsalted butter; * 4 cup powdered sugar; * 2 tablespoon heavy cream; * 1/2 cup semi sweet baking chocolate, melted and cooled; * 1/2 cup unsweetened cocoa powder; assembly:; * 2 graham cracker, finely crushed; * 12-15 marshmallow