Add enough milk (from the total amount) to cover the marshmallows.
Make absolutely sure!! to keep your eyes on the microwave, as you heat the mug up using the "milk warming" program. As you heat it the marshmallows will puff up, so stop the microwave at that point.
Take the mug out and mix well to dissolve the marshmallows. Don't worry if they don't dissolve totally since the mug will be heated again.
Add the instant coffee, and mix very very well to make it foamy.
Add the rest of the milk to the mug, and mix mix mix again. Microwave again using the "milk warming" program.
Mix it very well again after reheating, and it's done.
Float more marshmallows on top, or add cinnamon or cocoa powder to taste.
Story Behind this Recipe
Marshmallows can be used to make all sorts of treats. I wanted to use them in a hot drink, but just adding them on top was too mundane...so I wondered what it would be like if I melted marshmallows? I wondered if I could put this foaminess to use, and came up with this recipe.
When melting the marshmallows, do not take your eyes off the microwave whatever you do! Just mix very very well. The more you mix the foamier it gets, so just keep mixing.