Anaheim peppers are mild, yet flavorful, often used for chile relleno. They add just the right touch to this hearty main dish, which is perfect for enjoying the late summer bounty of your squash garden or farmer's market. If they aren't available, substitute poblano peppers. Serve this casserole with a green salad on the side.
Preheat the oven to 400F. Lightly grease a baking tray and a 9x10-inch baking dish.
Slice squashes into 1/2-inch pieces and distribute in a single layer on the baking tray. Add the chopped pepper and roast until the squash appears about half done, 15 to 20 minutes. Remove the vegetables from the oven and set aside.
Reduce the heat to 350F.
While the squash roasts, slice the chicken breasts lengthwise. Place the chicken in the bottom of a medium saucepan or Dutch oven. Add just enough water to cover the chicken and season the water with 1/4 teaspoon of salt. Bring the pot to a simmer over medium heat; do not allow it to boil. Reduce the heat to low and simmer, covered, until the thickest part of the chicken breasts cook through, about 20 minutes. Remove the chicken to a plate and allow it to cool. Pour 1/2 cup of the broth into a heatproof measuring cup; reserve the rest for another use or discard.
While the chicken cools, in the same saucepan, whisk together the milk, cornstarch, ground chile, 3/4 teaspoon salt, and black pepper. Stir in the 1/2 cup of warm chicken broth and stir the mixture over medium heat until it thickens and begins to bubble, about 5 minutes.
Remove the white sauce from the heat. Spoon 1/2 cup sauce into the baking dish and top with 3 corn tortillas, tearing the tortillas as needed to arrange them in a single layer.
Use two forks to shred the chicken, then stir it into the sauce along with the cooked squash and peppers, 1½ cups of cheese, and chile flakes if using. Spread half of the mixture in the baking dish, top with three corn tortillas, then with the other half of the chicken mixture. Top with halved cherry tomatoes and sprinkle with the remaining 1/2 cup of cheese.
Bake until the sauce bubbles and the casserole is golden brown on top, about 30 minutes. Serve promptly.
11 servings
8 servings (8 cups)
* The % Daily Value (DV) tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.