Puréed Potatoes With Lemon

Peel the potatoes and cut them into 1 1/2- to 2-inch chunks. Place the potatoes in a large saucepan and add enough water to cover by 1 inch. Add 2 tablespoons salt, cover and bring to a boil over high.

Uncover, lower the heat to a simmer and cook until the potatoes are very tender when pierced with a small paring knife, about 15 minutes. Drain and set aside.

Meanwhile, cut the butter in 1/2-inch dice and put it back in the refrigerator.

After the potatoes are drained, pour the milk into a small saucepan and heat over low just until it simmers. Turn off the heat.

Place a food mill fitted with the finest blade on top of the large saucepan. Process the potatoes into the pan. (Alternately, use a ricer or potato masher, making sure the potatoes are very smooth before proceeding.)

With the heat on low, vigorously whisk the cold butter into the potatoes several bits at a time, waiting for each addition to be incorporated before adding more butter.

Once all the butter has been integrated, slowly whisk in enough of the hot milk to make the potatoes the desired consistency, creamy but still thick. Add 2 teaspoons salt and 1 teaspoon pepper. Whisk in the lemon zest, reserving some for garnish, if desired. Season to taste, and serve hot. Sprinkle with reserved lemon zest just before serving.