Bring a large pot of salted water to a boil over high heat. Wash and peel potatoes and cut into 2-inch chunks. Add to water and boil over medium heat until potatoes are soft, about 15 minutes. Drain potatoes in a colander.
Place hot drained potatoes in a large bowl along with butter and cream cheese. Sprinkle kief or finely ground hash over bowl. Use an electric hand mixer to whip potatoes until all ingredients are well combined and little or no lumps remain, according to your preference. Season to taste with salt and pepper.