Place the peeled and quartered potatoes in a large pot and cover with cold water. Add salt and bring to a boil.

Cook the potatoes for about 20 minutes or until tender. Drain and return to the pot.

In a separate pot, melt 2 tablespoons of butter over medium heat. Add the shredded cabbage and sauté for about 5-7 minutes until softened.

Add the heated milk, remaining butter, and cooked cabbage to the drained potatoes. Mash until smooth and creamy.

Stir in the chopped green onions, and season with salt and pepper to taste.

Transfer the colcannon to a serving dish and top with additional butter if desired. Serve warm.