Root Vegetable Gratin

Classic Béchamel

• 6 cups whole or 2-percent milk
• 8 tablespoons unsalted butter (1 stick)
• ½ cup all-purpose flour
• Pinch ground nutmeg
• Salt and freshly ground black pepper

Root Vegetable Gratin

• 1 tablespoon unsalted butter
  
  

  For the Classic Béchamel:

  Heat the milk in a saucepan over medium heat until it is steaming hot (do not let it boil). Keep it at this temperature.

  Melt the butter in a heavy-bottomed saucepan over medium-low heat. Stir in the flour and cook, stirring constantly, until the paste bubbles, 2 to 3 minutes; don’t let it brown. Whisk in the hot milk and nutmeg and bring to a boil. Cook, whisking constantly, until the sauce thickens, 5 minutes. Season with salt and pepper to taste. Lower the heat and cook, stirring, for 2 to 3 minutes more.

  For the Root Vegetable Gratin:

  Preheat the oven to 350°F. Grease a 12- to 14-inch round baking dish or a 13 × 9-inch rectangular baking dish with the butter.

  Pour the béchamel into a saucepan and bring it to a simmer over low heat. Remove the pan from the heat, add the whole dried chiles, and steep for about 10 minutes. Remove and discard the chiles.

  Arrange half of the russet potato slices in a single layer on the bottom of the prepared baking dish. Top with a third of the red pepper strips. Season with salt and pepper to taste. Spread 1½ cups of the béchamel evenly over the potatoes and red pepper strips. Sprinkle with 1 cup of the cheddar. Arrange the sweet potato slices on top, slightly overlapping, in a spiral pattern. Season with salt and pepper, and top with another third of the red pepper strips. Again top with 1½ cups béchamel followed by 1 cup cheddar. Add the slices of rutabaga, slightly overlapping in a spiral pattern, and strew with the remaining red pepper strips. Add 1½ cups béchamel followed by 1 cup cheddar. For the final layer, arrange the remaining slices of russet potato on top, slightly overlapping, in a spiral pattern. Season with salt and pepper. Spread the remaining 1½ cups béchamel and 1 cup cheddar on top.

  Cover the dish with aluminum foil and bake for 1¼ hours. Remove the foil and bake until the top of the gratin is bubbly and nicely browned, about 20 minutes. A knife inserted in the center of the gratin should easily pierce the fully cooked, soft root vegetables. Serve piping hot.

  Variations

  • To lighten this dish, make a cornstarch/water slurry, stir it into chicken broth, and simmer until it achieves a béchamel-like consistency. Use in place of bechamel.

  • Omit the chiles and/or roasted red bell pepper.

  • Substitute turnips for the rutabaga.