Homemade Hostess Cupcakes

INGREDIENTS

• :
• 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
• 1 cup marshmallow creme
• ¼ cup unsalted butter, at room temperature
• ½ cup powdered sugar
• 2½ ounces bittersweet chocolate, finely chopped
• ¼ cup heavy cream
• 1 cup powdered sugar
• 1 tablespoon whole milk
• Splash vanilla extract