CHICKEN AND TORTILLA AZTEC CASSEROLE
For the sauce
3 tablespoons vegetable oil
1 medium white onion, chopped (1/2 cup)
2 cloves garlic, minced or pressed
2 pounds ripe tomatoes, cored and pureed, or whole canned tomatoes, drained and pureed (to make about 5 cups tomato puree)
1/2 teaspoon dried oregano
1 bay leaf
1 teaspoon kosher or coarse sea salt
For the tortillas
1 cup vegetable oil, or more as needed, for frying the tortillas
8 to 10 corn tortillas (9 ounces total)
4 cups cooked, shredded chicken
4 cups fresh corn (may substitute frozen; see NOTES)
1 pound poblano chili peppers, roasted, peeled, seeded and cut into rajas (see NOTES)
1 cup Mexican cream (crema), Latin-style cream, creme fraiche or heavy cream
12 ounces grated Oaxaca, mozzarella, Monterey Jack or mild white cheddar cheese (about 3 cups)
For the sauce: Heat the oil in a large saucepan over medium heat. Stir in the onion and cook until soft and translucent, stirring occasionally, about 6 minutes. Stir in the garlic and cook until fragrant, 30 seconds to 1 minute. Add the tomato puree, oregano, bay leaf and salt and cook for about 10 minutes, stirring occasionally, until the sauce thickens and darkens in color. Remove from the heat and discard the bay leaf.
For the tortillas: Cover a large plate or baking sheet with several layers of paper towels. Pour the oil into a medium 10-inch skillet to a depth of 1/4 inch (about 1 cup). Heat over medium-high heat until hot but not smoking, about 2 to 3 minutes. Working with one tortilla at a time, use a pair of tongs to pass the tortilla through the oil for 10 to 15 seconds per side; this will make the it pliable and resistant to the sauce. The tortilla will first appear to be softening and then will become barely crisp, and its color will darken. Drain on the paper towels.
To assemble: Spread one-third of the tomato sauce on the bottom of a 9-by-13-inch baking dish or the equivalent. Cover with half of the cooked chicken, half of the corn, half of the poblanos and one-third of the cream and cheese. Top with half of the tortillas, tearing them into large pieces if needed to make an even layer without much overlap. Repeat, adding one-third of the tomato sauce; the remaining half of the cooked chicken, corn and poblanos; and one-third of the cream and cheese. Top with a layer of the remaining tortillas, the remaining one-third of the sauce and the remaining cream and cheese.
When ready to bake, preheat the oven to 375 degrees. Cover the casserole dish with a lid or with aluminum foil. Bake for 25 minutes, then remove the lid or foil and bake for 15 minutes or until the top is bubbly and the cheese has melted. Serve hot.
NOTES: To create rajas, or strips, char or roast the chilies, either by placing them under the broiler or directly on a grill or hot skillet. Roast for 6 to 9 minutes, turning every 3 to 4 minutes, until they are charred and blistered but not burned. Immediately place in a plastic bag; close the bag tightly and cover with a kitchen towel; this will facilitate skinning. One by one, remove each chili from the bag, peel off the skin and lightly rinse the chili with water. Cut out the stem and cut each pepper in half. Remove and discard the seeds, then cut the peppers into strips 1/2-inch wide and an inch long.
Frozen corn will make the dish watery if it is not precooked to remove moisture. First, defrost the corn completely. Heat a large skillet or saute pan over medium-high heat. Add 1 teaspoon of unsalted butter; when it has melted, add the corn and cook for 2 minutes, stirring frequently.