The “parent” of 里芋 satoimo (Japanese taro) are on the market, they are called 親芋 oyaimo parent potato. That’s not classic sauce béchamel, but the texture is similar.
Let’s start with the beans, well the side dish :
Making pattzuki bean patties with azuki, miso, sesame, onion, parsley, kabocha skin. It is spiced by turmeric (very visible here) and paprika powder plus a few chili flakes.
The redness comes while cooking. Served with leaves of komatsuna.
Oya imo, a big taro.
Here is a photo of family of 親芋 oyaimo, the parent with its kids and grand-kids :
from this blog いきもの は おもしろい！
I cut and peeled a thick slice, boiled till tender.
The sauce is green as it contains lots of fresh parsley.
Fry minced onion, garlic, feet of shiitake mushroom. Blend together silky tofu, white wine, a tbs of potato starch. Add into the pan. Season with salt, pepper. Simmer.
Let cool and pass in the blender with 2 volumes of fresh parsley per volume of sauce. Reheat slowly before serving.
The oyaimo with sauce and steamed stalks of komatsuna.