Meanwhile, place 3 marshmallows together on a foil-lined sheet tray, and place inside the oven. Turn on the broil setting, and watch carefully until marshmallows caramelize. Turn off oven and remove marshmallows. Set aside to cool slightly.
Pour milk into a mug. Stir in hot chocolate mix. Break up 1 marshmallow and stir it in until dissolved for extra marshmallow flavor, optional. Garnish with toasted marshmallows, a dollop of whipped cream, and a sprinkle of crushed graham crackers.