Boil the potatoes in plenty of lightly salted water until they are tender throughout when pierced with a sharp fork or knife point. Drain the potatoes well and put them through a ricer or a food mill or press them through a sieve. Do not puree the potatoes in a food processor—they will become gluey.
Working the potatoes as little as possible and using a wooden spoon or a rubber spatula, beat in the butter and the cream and season the potatoes to taste with salt and freshly ground pepper. Serve immediately or set aside and reheat in a casserole in a 350°F oven.
This recipe for mashed potatoes can be varied endlessly.
Foie Gras Mashed Potatoes:
Use ½ cup foie gras scraps, chopped into dice. Sear the scraps in a hot sauté pan, stirring until the foie gras is just cooked and has rendered some fat. Fold the liver and fat into the mashed potatoes instead of the butter.
Herbs and Cheese Mashed Potatoes:
Add ½ cup grated Hawthorne Valley, Swiss, or Parmesan cheese and 3 tablespoons herbs (garlic, chives, and parsley, for example) chopped into a paste to the potatoes before seasoning them.
Horseradish Mashed Potatoes:
Beat in 3 tablespoons prepared horseradish when you add the butter.
Olive Oil and Rosemary Mashed Potatoes:
Gently simmer 2 tablespoons chopped fresh rosemary in 4 tablespoons extra virgin olive oil for 5 minutes. Strain and add instead of the butter.
Sorrel Mashed Potatoes:
Beat in 2 tablespoons sorrel puree, (made from ¼ pound sorrel) when you add the butter.
Yukon Gold and Dill Mashed Potatoes:
Add 2 tablespoons chopped fresh dill to the potatoes and substitute 1/3 cup sour cream for the heavy cream.