Peel and chop your Yukon Gold potatoes into even pieces and place them in a large pot covered with cold salted water. Bring to a boil and cook for about 20 minutes, until fork-tender.

While the potatoes are boiling, heat Irish butter in a skillet over medium heat. Add chopped cabbage or kale and spring onions. Sauté for 5-7 minutes until softened and slightly golden.

Drain the cooked potatoes and transfer them to a mixing bowl. Mash them until ultra-smooth and creamy, keeping them warm.

Gently fold the sautéed vegetables into the mashed potatoes and gradually add warm milk until desired creamy consistency is reached. Incorporate sharp Irish cheddar if using.

Taste your dish and adjust seasoning with salt. Serve immediately while warm.