Make a bunch, separate them into small portions, and store in the freezer.This makes them convenient to use whenever you need them or even in bento lunch boxes.
In order for the refrigerator to not get too full, I always wrap things up in different sizes for practical use.This is one of those things.
It's even easier if you heat the sweet potatoes in the microwave!(But as for me, I like boiling them better.)This recipe is useful for mashing the potatoes: Recipe ID: 1990660 "The Fastest Way to Mash Potatoes (or Sweet Potatoes)"
Enjoy Japanese food around the world.