Potato Dumpling Japanese Imo-Dango Vegan

I made this food vegan, and it is a Japanese potato dumpling called Imo-Dango . I think this is the Hokkaido origin recipe. It is easy and good with beer!

Ingredients**
Potato 5 (about1lb)
Potato Starch 6TBS
Potato starch mix with water 1tsp each
Water 50ml
Mirin 1TBS
Soy Sauce 1.5TBS
Sugar 1TBS
Vegan Butter 2TBS