Root vegetable tubers are extremely healthy, mostly organic and dangerously delicious, as long as you don’t overcook them into mush. The best way to cook them is using a steamer so they do not come into contact with water, but steam, which does not make them soggy. I like arrowroot, a little bit of cassava as well as sweet potatoes (not in picture).
Cooking them this way also ensure they are done quicker so you save on fuel, and time.
I got my bamboo one from Healthy U but I don’t think they have many. Try getting some online.