I like it fried in a cast iron skillet with kielbasa. Add some bacon grease and a little bacon even better. Wife usually adds a few onions too. Plenty of salt.
Coleslaw made with home made mayonnaise made from olive oil and eggs would be ok too.
Both of those are keto unless you eat the whole cabbage yourself. That might be enough carbs to knock you out of ketosis. But it would still be considered low carb probably. :-)