In a small saucepan, combine the sugar and water. Stir the mixture occasionally until the sugar dissolves, and it comes to a simmer. Simmer for 5 minutes.
In the meantime, place the marshmallows on a foil-lined baking sheet. Use a culnary torch or an oven broiler to toast the marshmallows.
Add the toasted marshmallows and vanilla into the syrup and stir until the marshmallows have fully melted and combined with the syrup.
Allow the syrup to sit for 10 minutes, then pass it through a fine mesh sieve into a container.
Iced S'mores Latte
Line a coffee glass with melted chocolate on the inside (optional, for aesthetics!)
Add the chopped chocolate and toasted marshmallow syrup to the glass, and brew the espresso directly over it.
Mix the chocolate and espresso together until the chocolate has melted.
Pour the milk over the espresso.
Add in ice to fill up the cup.
Top with whipped cream, crushed graham crackers, and more toasted marshmallows. Enjoy!
Notes
Store the extra toasted marshmallow syrup in an airtight container in the fridge, and enjoy for up to 1 week. If you'd like to make a smaller batch, just divide the ingredients by 2 or by 4 to not have a weird decimal of marshmallows needed!