Halve large potatoes, small ones can be left whole. Place potatoes in a deep pot, cover with water. Place a lid on potatoes and bring them up to a boil. Uncover, salt the water and cook until tender, 12 to 15 minutes. Drain potatoes and add back to the hot pot. Add butter, milk or cream and cheese and smash the potatoes to desired consistency. Season with salt and pepper, to taste.