In a medium saucepan, combine the potatoes, water, and 2 teaspoons of the salt and bring to a boil over high heat. Reduce the heat to medium and cook until tender, 8 to 10 minutes. Remove from the heat and drain in a colander.

Return the potatoes to the pot over set over low heat, add the cream, roasted garlic, the remaining 1 teaspoon salt, and the white pepper and mash vigorously with a potato masher until fairly smooth. Stir in the butter and remove from the heat. Serve immediately.

Note: To make roasted garlic, preheat the oven to 400º F. Combine garlic cloves with 1 teaspoon olive oil,  a sprinkle of salt, and 1 turn freshly ground black pepper on a sheet of aluminum foil. Fold the edges of the foil together to form a bag and roast until tender, for about 40 minutes. Use immediately, or refrigerate in a little olive oil in an airtight container for 2 or 3 days.