Chop the potatoes into small equal sized pieces. Note: Don't peel them unless you don't own a food mill.
Put in a pot and add enough water to cover.
Bring to a boil, then simmer until soft.
Process the potatoes through a food mill (if you have one) otherwise mash them with a potato masher.
Add about ¼ cup of buttermilk and 4 tablespoons of butter. Mix to combine.
Season with kosher salt and white pepper to taste.
For the cabbage
Shred the cabbage. Then wash and drain it in the sink.
Bring a large pot to a boil with 1 tablespoon of salt and 1 tablespoon of sugar.
Add the cabbage.
Boil for 2-3 mintues until the cabbage has soften but is not mushy.
Drain the cabbage and then mix into the prepared potatoes.
Notes
I call for white pepper in this recipe for 2 reasons: 1) white pepper won't stand out in appearance like black pepper 2) The milder flavor of white pepper doesn't overwhelm the rest of the dish