With a potato masher or a potato ricer, mash the potatoes with the butter. Stir in the garlic cream and milk until the mixture is just blended. Add the cheese and heat the purée on medium to low heat, stirring with a wooden spoon until the cheese has melted and the purée is very elastic. Add milk, if needed. Season with salt and pepper. Delicious with Beer-Braised Duck (see recipe), a roast, steaks, sausages, or Spice-Rubbed Pork Chops (see recipe).