The frosty version of the campfire classic is bound to be hit on a hot summer's day.
Toast 6 marshmallows over a gas flame or in a broiler for about 30 seconds on each side. Thread the remaining 3 marshmallows on a skewer.
Blend chocolate ice cream and milk until smooth and just pourable. Add toasted marshmallows and pulse to combine. Spread some hot fudge sauce on the sides of a tall glass. Add 1 scoop vanilla ice cream. Crumble in the graham cracker. Top with some hot fudge. Top with milkshake; do not fill to the top of the glass or it will overflow when toppings are added. Pipe on whipped cream, as desired.
Dip a few pieces of graham cracker in hot fudge and arrange in the whipped cream. Toast the skewered marshmallows, then arrange the skewer in the milkshake. Serve with a straw, bowl, and spoon.