I am smug like a smug thing and posting about it very belatedly.
Why am I smug?
I am smug because, using
this recipe, substituting light agave nectar for corn syrup and granulated xylitol for granulated sugar (ETA: and powdered xylitol for confectioner's sugar), and using Kolatin brand gelatin ...
... I have successfully made kosher sugar-free marshmallows.
They taste like marshmallows. They have the right texture. You can toast them.
I am pretty sure this means I win. :D :D :D