Colcannon is a dish enjoyed all over Ireland year-round, though it's particularly associated with Halloween night, the eve of the Celtic new year.
- 4 lb. large red potatoes (about 9), peeled and quartered
- 12 tbsp. butter
- 1⁄2 small head cabbage, cored and thickly sliced
- 2 lightly packed cups chopped greens (any combination of spinach, parsley, kale, or broccoli or cauliflower leaves)
- 1 1⁄3 cups milk
- 4 scallions, green part only, chopped
- Salt and freshly ground black pepper
Put potatoes into a steamer basket over a large pot of simmering water and steam over medium heat until tender, about 45 minutes.
Meanwhile, bring 1⁄2 cup water and 2 tbsp. of the butter to a boil in a small pot over medium-high heat. Add cabbage, reduce heat to medium-low, and cook until just tender, about 15 minutes. Drain well, discarding liquid, and set aside.
Melt 2 tbsp. of the butter in a large skillet over medium-high heat. Add chopped greens and sauté until just wilted, about 2 minutes. Add cabbage and cook until heated through, 1–2 minutes, then transfer to a large mixing bowl.
Put milk, scallions, and remaining butter into a small pot and bring to a simmer over medium heat. Simmer until scallions are softened, 1–2 minutes, then add to cabbage mixture and cover to keep warm.
When potatoes are done, add to cabbage mixture and mash with a potato masher until fluffy and smooth with some chunks. Season to taste. Serve hot.