by Super User Featured Chef Adapted from www.bonappetit.com.
Colcannon is a traditional Irish dish made from mashed potatoes and kale or cabbage, with a million different variations. This take on it calls for Savoy cabbage, garlic, and leeks.
Place the potatoes in a saucepan and cover with water. Add a pinch of salt. Bring to a boil over medium-high heat, reduce heat and simmer 30-40 minutes, until easily pierced with a fork. Drain and peel as soon as they are cool enough to handle.
Melt 4 tablespoons of the butter in a large saucepan over medium heat. Add the leeks and cook, stirring frequently, for 8-10 minutes, until very tender. Stir in the garlic and cook another 3 minutes, until the leeks begin to turn golden brown and the garlic is fragrant. Fold in 1 cup of the cabbage, and cook, stirring, until wilted. Add the milk and cream and bring to a simmer. Add the peeled potatoes and last 1 cup of cabbage. With the pot over low heat, use a potato masher to mash coarsely, and stir until heated through. Season to taste with salt and pepper.
Turn the colcannon into a large serving dish. Top with the last 2 tablespoons of butter, and sprinkle with the sliced green onion. Enjoy hot.