Boil potatoes in salted water until tender. Drain. Add salt and pepper to taste and parsley if desired. Add sour cream and 4 Tbsp. of butter. Mash or whip until desired consistency.
Fry bacon over medium heat until done.
Saute onion in bacon drippings
Drain most of bacon drippings.
Add 2 Tbsp. of butter to bacon drippings and onions.
Add cabbage to butter and onion mixture and saute for 5 minutes.
Slowly add slaw mixture to potato mixture.
Chop bacon into small bits. Add to top.