Peel and cut into chunks the potatoes and celery roots, and boil
in plenty of water until soft (took me about half an hour but I
think it depends on how old and tough the celery root is).
While these are boiling, chop the onion and cabbage into small
pieces (I made about 1/2 inch squares). Saute in a bit of cooking
spray for a few minutes. Then add about 1/4 cup water to the pan
(I used a wok), cover, and let cook, stirring once in a while,
until onion is browned and cabbage is tender. Chop the scallions
after adding the water and throw them in after 10 minutes or so.
Drain potatoes and celery root, place in a bowl, and mash with a
wooden spoon or potato masher (no food processor! it turns
potatoes to glue) -- it should be slightly lumpy. Add the
cabbage-onion-scallion mixture and blend well. Season with salt
and pepper to taste.
