Chef David Scribner likes the extra body and flavor that rutabaga, celeriac and butternut squash bring to this gratin. The starch in the potatoes melds with the cream to give a sense of cheesy goodness.
- Nonstick cooking oil spray, for the baking dish and for the crumb topping
- 5 medium (1 1/2 pounds to 2 pounds) Yukon Gold potatoes, peeled
- 1 to 1 1/2 cups heavy cream (may substitute low-sodium chicken broth)
- Kosher salt
- Freshly cracked black pepper
- 1 tablespoon minced thyme leaves
- 2 medium (3/4 to 1 pound) rutabagas, peeled
- 1 pound butternut squash (neck only), peeled
- 1 large (about 1 1/2 pounds) celeriac (celery root), peeled
- 2 tablespoons melted unsalted butter or pareve margarine
- 1 cup fresh bread crumbs
- 3 tablespoons freshly grated Parmigiano-Reggiano cheese (optional)
Preheat the oven to 350 degrees. Spray a 9- by 13-inch baking dish with nonstick cooking oil spray.
Use a mandoline or very sharp knife to cut the vegetables into very thin slices (keep the peeled potatoes in a bowl of cold water until ready to cut).
Build a total of 12 layers in the baking dish with the sliced vegetables, in the following manner: a layer of potatoes, then a layer of rutabaga; a layer of potatoes, then a layer of squash; a layer of potatoes, then a layer of celeriac. Repeat for a second round. Drizzle a little of the cream between each layer, making sure to reserve at least 1/2 cup for covering the top of the gratin evenly; also, season lightly with salt, pepper and some of the thyme between each layer. Be sure to press each layer down gently.
Cover tightly with aluminum foil. Place the baking dish on a baking sheet (to guard against oven spills). Bake for about 45 minutes.
Meanwhile, melt the butter or margarine in a small saute pan over medium-low heat. Add the bread crumbs and cheese, if using, mixing well. Remove from the heat.
Remove the gratin from the oven and uncover; position the top oven rack 4 to 6 inches from the broiling element. Preheat the broiler.
Spread the crumb topping evenly across the gratin. Spray the topping lightly with nonstick cooking oil spray. Return to the oven for a few minutes under the broiler, just until the gratin is browned and bubbling. Let sit for at least 5 minutes before serving.
From David Scribner, chef at Surfside restaurant in Glover Park.
Tested by David Scribner.
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