Add all the ingredients except Baileys into a medium pot. Whisk until corn starch is dissolved. A spiral/sauce whisk (pictured) is perfect for this recipe although a balloon whisk also works well.

Place the pot on a burner and bring to a boil over medium heat, stirring often. Reduce the heat to low and cook for 1 minute (to cook off floury taste of corn starch), whisking often (make sure that nothing sticks to the bottom and sides of the pot).

Let stand for 2 minutes to cool slightly (whisk it from time to time) then whisk in Baileys.

Pour into a heat-proof mug. Top with mini marshmallows (optional).

Enjoy!

Calories = 1 serving (whole recipe). This is only an estimate!