Active Time

　　20 min

　　Total Time

　　35 min

　　Truffles add a flavorful woodsy note, but if you make this French-influenced celery-root purée without them, it will still be delicious.

　　

Ingredients

Makes 8 to 10 side-dish servings

　　3 lb celery root (sometimes called celeriac; 2 large), peeled with a knife and cut into 1/2-inch pieces (8 cups)

　　1 3/4 lb boiling potatoes (3 large), peeled and cut into 1/2-inch pieces

　　1 cup heavy cream

　　4 oz black truffle butter* or 1 stick (1/2 cup) unsalted butter

　　1 teaspoon salt

　　1/4 teaspoon black pepper

　　

Step 1

Cover celery root and potatoes with cold salted water by 2 inches in a 4- to 6-quart heavy pot, then simmer, covered, until celery root is very tender, about 15 minutes.

　　

Step 2

While vegetables are simmering, bring cream, truffle butter, salt, and pepper just to a simmer, stirring until butter is melted.

　　

Step 3

Drain vegetables in a colander and transfer to a food processor. Add hot cream mixture in a steady stream, pulsing until smooth. (Alternatively, mash vegetables with hot cream mixture using a potato masher.)

　　Cooks' note:

　　Purée can be made 1 day ahead and cooled, uncovered, then chilled, covered. Reheat in an ovenproof dish, covered, in the oven or microwave until hot. *Available at specialty foods shops and D'Artagnan (800-327-8246).