Active Time

　　20 min

　　Total Time

　　45 min

　　

Ingredients

Makes 4 to 6 servings

　　Unsalted butter for greasing baking pan

　　1 cup heavy cream

　　1/2 cup whole milk

　　1 teaspoon fresh thyme

　　1 teaspoon salt

　　1/2 teaspoon black pepper

　　1 lb celery root (sometimes called celeriac)

　　1 lb carrots (4 large)

　　2 tablespoons all-purpose flour

　　2 oz Gruyère, coarsely grated (1/2 cup)

　　

Step 1

Put oven rack in middle position and preheat oven to 400°F. Butter an 8-inch flameproof ceramic dish or metal baking pan.

　　

Step 2

Simmer cream, milk, thyme, salt, and pepper, uncovered, in a 4-quart heavy saucepan over moderate heat until reduced to about 3/4 cup, 10 to 13 minutes.

　　

Step 3

While mixture is simmering, peel celery root with a sharp knife, then cut into large wedges. Coarsely grate carrots and celery root in a food processor. Toss with flour in a large bowl until coated well, then add to cream mixture and simmer, uncovered, stirring frequently, 5 minutes.

　　

Step 4

Transfer to baking dish and smooth top. Sprinkle evenly with Gruyère and bake until bubbling, about 10 minutes.

　　

Step 5

Turn on broiler and broil gratin 5 to 6 inches from heat until top is golden brown, 3 to 5 minutes. Let stand 10 minutes before serving.