Colcannon Mashed Potatoes

Place the peeled and quartered potatoes in a large pot and cover with cold water by 1 inch. Add 1 teaspoon of salt to the water. Bring to a boil over high heat, then reduce the heat to medium and simmer for 15-20 minutes, or until the potatoes are very tender when pierced with a fork.
While the potatoes cook, melt 2 tablespoons of butter in a large skillet over medium heat. Add the sliced cabbage and cook, stirring occasionally, for 10-12 minutes until it is wilted and softened. Stir in the sliced scallions and cook for 1 minute more. Remove the skillet from the heat.
In a small saucepan, combine the whole milk and heavy cream. Warm over low heat until just steaming; do not boil. Keep warm.
Drain the cooked potatoes thoroughly and return them to the hot pot. Let them sit for a minute off the heat so any residual moisture evaporates.
Mash the potatoes with a potato masher until smooth. Gradually pour in the warm milk and cream mixture, stirring with a wooden spoon or rubber spatula until fully incorporated and the potatoes are creamy.
Gently fold the cooked cabbage and scallions into the mashed potatoes until evenly distributed. Season generously with additional salt and black pepper to taste. Transfer to a serving bowl, make a well in the center, and place the remaining 2 tablespoons of butter in the well to melt before serving.