Bring a large pot of water to a boil and blanch the kale for 2 minutes until tender. Drain thoroughly, squeeze out excess moisture, and set aside on paper towels to dry completely.

Heat 2 tablespoons of olive oil in a large nonstick skillet over medium-high heat. Season the chicken pieces with salt and pepper, then sear in the pan until golden on a few sides, about 4 minutes. Transfer the chicken to a bowl (it won’t be fully cooked yet).

Reduce the heat to medium and add another tablespoon of olive oil if needed. Add the chopped onion and sauté until soft and translucent, about 4 minutes.

Sprinkle the flour over the onions. Cook, stirring constantly, for 1 minute to eliminate the raw flavor of the flour.

Gradually whisk in the milk, continuing to stir until the flour dissolves completely. Add the chicken broth and bring the mixture to a simmer over medium-high heat.

Let the sauce simmer for 2 minutes until it slightly thickens. Stir in the blanched kale, chopped artichokes, cayenne, chicken, and any juices from the resting chicken.

Add 3 tablespoons of Parmesan cheese, stirring to combine everything evenly. Taste and adjust seasoning if needed.

Preheat your oven broiler to high. Lightly spray an 8-inch broiler-proof baking dish with nonstick cooking spray. Spoon the casserole mixture into the dish in an even layer.

Top with the panko breadcrumbs and the remaining tablespoon of Parmesan cheese.

Place the casserole under the broiler, about 3 inches from the heat source, and broil for 3 minutes until the top is golden and crispy. Serve immediately for the best texture and flavor.