Peel potatoes (if you fancy, sometimes I leave them unpeeled), chop into 1 inch segments, place in a large pan, cover in water and bring to the boil. Simmer until tender.
Meanwhile, thoroughly wash your kale, remove the tough stalks and chop finely. Heat a dry non-stick pan and gently wilt the kale until it has softened but still retains it's gorgeous green colour. Set aside (you might want to chop it up finer again after it is cooked).
When the potatoes are tender, drain and return to the hob for about 30 seconds to evaporate off the extra moisture. Mash with the butter, cheese and milk, adding more milk if you want a creamier consistency.
Stir in the cooked kale and season well to taste. Serve immediately.