Is there any way to make MMF less sweet?

not really because it's made of Marshmallows and icing sugar which are both pretty much pure sugar lol My suggestion would just be to make sure it isn't too thick and therefore less to eat and not as sweet

Try adding a pinch- and I do mean a pinch more salt.

i was just thinking maybe the type of marshmallow being used could help because some i have tried are alot sweeter than some others...