Cook potatoes in boiling water for 15 min. Drain well, put them back into pan; add milk and mash smooth with salt & pepper.
Melt butter in skillet and cook cabbage until soft. Add to the potatoes with the cheese. Mix together and form into 4 cakes.
Fry bacon in the skillet until crisp. Remove bacon and keep warm. Add the potato cakes to skillet and cook until well browned (both sides) and slightly crisp. Add vegetable oil if there is not enough drippings from bacon. Serve with the bacon.