Cheesy Summer Squash Casserole

Preheat oven to 375 degrees F. Spray an 8-inch square casserole dish with cooking spray.

Bring a large pot of water to a boil over high. Add squash, onion, bell pepper and chiles; cook until squash it's just tender, about 6 minutes. Drain well. Transfer mixture to a baking sheet lined with paper towels; spread into a single layer and pat dry. Set aside.

Stir together cheese, mayonnaise, black pepper and salt in a large bowl; fold in cooked squash mixture. Transfer to prepared casserole dish. Stir together panko and oil in a small bowl; sprinkle over squash mixture.

Bake in preheated oven until mixture is bubbling and golden brown, about 25 minutes. Let cool at room temperature 5 minutes.