Place the peeled and cubed potatoes in a large pot, cover with cold water, and add a pinch of salt. Bring to a boil and cook until tender, about 20 minutes.

In the last 5 minutes of cooking the potatoes, add the chopped kale to the pot to blanch.

Drain the potatoes and kale in a colander. Return them to the pot and add butter, milk, salt, and pepper. Mash until smooth and creamy.

Fold in the sliced green onions and mix well. Adjust seasoning to taste.

Serve hot as a side dish, garnished with additional butter if desired.