SOUTHWESTERN SWEET-POTATO GRATIN

Southwestern Sweet-Potato Gratin image

Provided by Martha Stewart

Number Of Ingredients 12

Unsalted butter, for baking dish
4 large sweet potatoes (about 4 pounds), peeled and thinly sliced into rounds
Coarse salt and freshly ground pepper
1 1/2 cups grated Chihuahua or Monterey Jack cheese (6 ounces)
1 1/2 cups Cotija or French feta cheese, crumbled (6 ounces)
1 small onion, thinly sliced
1 teaspoon finely chopped canned chipotle chile in adobo (optional)
1/4 cup plus 2 tablespoons homemade or low-sodium store-bought chicken stock, or water
1/4 cup finely chopped fresh cilantro leaves
1 cup crushed tortilla chips
Lime wedges, for garnish
Mexican crema or sour cream, for garnish (optional)

Steps:

Preheat oven to 350 degrees. Butter a 9-by-13- inch baking dish; set aside. Toss potatoes with 1 1/2 teaspoons salt and 1/4 teaspoon pepper. Arrange half of potatoes in buttered dish, overlapping slices. Sprinkle with half of each cheese. Top with onion.
Stir chipotle (if desired) into stock; drizzle over onion. Sprinkle with half the cilantro. Top with remaining potatoes; sprinkle with remaining cheeses and cilantro. Scatter chips on top.
Cover with foil; bake 30 minutes. Remove foil; bake until very tender and top is well browned, about 30 minutes more. Let cool slightly before serving. Serve with limes, and with crema, if desired.