In a blender, combine vanilla ice cream, milk, brownie chunks, mini marshmallows, chocolate syrup, and vanilla extract. Tip: For a thicker shake, use slightly less milk.

Blend on high speed until smooth and creamy, about 30-45 seconds. Tip: Pulse a few times first if your blender struggles with thick mixtures.

Pour into two tall glasses, leaving room at the top for toppings.

Toast the large marshmallows using a kitchen torch or under the broiler until golden brown. Tip: Watch closely as marshmallows burn quickly!

Skewer the toasted marshmallows and place on top of each milkshake.

Drizzle with additional chocolate syrup and sprinkle with graham cracker crumbs if desired.