Simply heat a knob of butter and cook the remaining finely shredded cabbage for 5 mins, so it's still just a little crunchy.
Tip the potatoes into a large saucepan of water. Bring to the boil, then simmer for 15-20 mins, or until the flesh is tender when pierced.
Meanwhile, heat quarter of the butter in a
saucepan, then fry the bacon and half the cabbage for 5 mins (see Kevin’s tip, below, for how to use remaining cabbage). Turn off the heat and set aside. Drain potatoes in a colander and peel while still hot.
Mash potato until smooth. Heat cream with remaining butter and, when almost boiling, beat into the potato. Add bacon and cabbage to potato and mix. Season if you want.