Ingredients

　　3 1/2 pounds Jerusalem artichokes*

　　1 pound boiling potatoes

　　1 tablespoon salt

　　3 cups milk

　　3 tablespoons unsalted butter, softened

　　*available at specialty produce markets and many supermarkets

　　Peel Jerusalem artichokes and cut into 2-inch pieces. Peel potatoes and cut into 3/4-inch pieces. In a 5-quart kettle combine artichokes, potatoes, salt, and milk with enough water to cover vegetables by 2 inches and simmer until vegetables are tender, about 25 minutes. Drain vegetables in a colander and return to kettle. With a potato masher mash vegetables with butter and salt and pepper to taste until smooth. Vegetables may be made 3 days ahead and chilled, covered. Bring vegetables to room temperature before reheating, covered.