For the Cupcakes:
3 ounces bittersweet chocolate, chopped fine
⅓ cup Dutch-processed cocoa powder
¾ cup brewed coffee, still hot
¾ cup bread flour
¾ cup granulated sugar
½ teaspoon baking soda
½ teaspoon salt
6 tablespoons vegetable oil
2 eggs
2 teaspoons white vinegar
1 teaspoon vanilla extract

For the Filling:
1 cup marshmallow creme
¼ cup unsalted butter, at room temperature
½ cup powdered sugar

For the Ganache Frosting:
2½ ounces bittersweet chocolate, finely chopped
¼ cup heavy cream

For the White Icing:
1 cup powdered sugar
¼ cup unsalted butter, at room temperature
1 tablespoon whole milk
Splash vanilla extract