Make sure everything gets coated in the olive oil and seasonings so nothing dries out during the long bake.
The butter squares melt over everything during baking and create a rich, savory pan sauce at the bottom of the dish. Spoon it back over the top before serving.
For extra color, broil for the last 3 to 5 minutes until the top gets golden and slightly crispy.
Cut the potatoes and chicken into similar-sized pieces so everything finishes cooking at the same time.