Step 1

Adjust an oven rack to the top third position and heat to 475 F. Pat the chicken dry with paper towels. Season generously on both sides with salt and pepper.

Step 2

Heat a large (12-inch) cast-iron or oven-safe, deep-sided skillet over medium-high heat. Add oil and 1 tablespoon butter. Once the butter has melted, add the chicken and cook until browned and nearly cooked through, about 5 minutes per side. (The chicken will finish cooking in the oven.) Transfer to a plate.

Step 3

Reduce the heat to medium. Add spinach and artichokes. Cook, stirring occasionally, for 2 minutes.

Step 4

Stir in 1 tablespoon butter. Once melted, stir in flour and cook for 30 seconds. Pour in milk, stirring frequently, until the mixture comes to a simmer. Cook until thickened, stirring occasionally, 2 to 3 minutes. Stir in cream cheese, mozzarella, 1/4 cup Parmesan, 1 teaspoon salt, 1/2 teaspoon pepper and 1/2 teaspoon garlic powder, until the cheeses have melted. Taste and season with more salt, if desired. Return the chicken thighs to the skillet, spacing them evenly apart into the spinach-artichoke mixture. Turn off the heat.

Step 5

In a medium microwave-safe bowl, melt the remaining 2 tablespoons butter, about 45 seconds. Stir in the remaining 1 teaspoon garlic powder and 1/4 teaspoon salt, then add the cubed bread and toss until well coated. Scatter bread cubes over the skillet. Sprinkle with the remaining 2 tablespoons Parmesan.

Step 6

Bake the chicken until browned and bubbling, 6 to 8 minutes. Rest for 5 minutes before serving.