1/2 cup unsalted butter
1/4 cup whole milk
3/4 teaspoon kosher salt
1/2 teaspoon black pepper
4 large thinly sliced shallots
1 large halved and thinly sliced leek
1 bunch stemmed and coarsely chopped kale
1 head cored and coarsely chopped napa cabbage
1/4 teaspoon freshly grated nutmeg
1/4 teaspoon salt
2/3 cup tops, chopped green onion
Cut and steam the potatoes until tender. Return to the still hot pot and add 1/4 cup butter, milk, kosher salt and 1/4 teaspoons pepper. Mash together. Melt the remaining butter in a large pot over medium heat. Add shallots and leeks. Sauté until they begin to soften. Add the kale and toss until soft and wilted but still bright green, about 3 minutes. Add the cabbage and toss until tender-crisp, about 8 minutes. Sprinkle with nutmeg, salt and the remaining pepper. Mix the cabbage and mashed potatoes together well. Sprinkle with the green onion slices before serving.