How to Make It
Set a steamer basket inside a medium pot with 1-inch of water in the pot. Bring the water to a boil, then place the potatoes in the steamer basket and cook, covered, 10 minutes. Add the kale on top of the potatoes, then continue to cook, covered, until the potatoes and kale are tender, about 10 minutes more.
Transfer the potatoes and kale to a large bowl. Season the colcannon with 1 teaspoon salt and 1/2 teaspoon pepper, then add the cream and butter and mash with a large fork until the butter is melted and combined and the potatoes are mashed. Season with salt and pepper to taste and serve.