Place the potatoes and garlic in a saucepan. Cover with 1 to 2 inches cold water and season generously with salt. The water should taste like the sea. TASTE IT! If the water is under seasoned at this point it will be hard to have a well-seasoned end product. Bring the pan of water to a boil, reduce to a simmer and cook until the potatoes are fork tender, 15 to 20 minutes. Drain the potatoes and garlic well and pass through a food mill or ricer. DO NOT use a food processor or blender. It will result in a very sticky and rubbery end product. While passing the potatoes, bring the heavy cream to a boil in a small saucepan. Once the cream has come to a boil, remove from the heat. While the potatoes are still hot, add one-third of the cream and 2 pats of the butter and stir vigorously into the potatoes. Repeat this process two more times until all of the cream and butter has been incorporated. Taste the potatoes for seasoning, and add salt if needed. Serve immediately or cover with foil and keep warm in an oven on low heat.