01 - Preheat the oven to 400°F. Lightly grease a large baking dish with cooking spray or a small amount of oil.
02 - Arrange the sliced onions and half the lemon slices evenly in the bottom of the prepared baking dish, creating a bed for the chicken.
03 - Pat chicken breasts dry with paper towels and place them on top of the onions and lemon slices in a single layer.
04 - In a small bowl, whisk together olive oil, melted butter, minced garlic, dried oregano, dried thyme, salt, and black pepper until well combined.
05 - Brush or spoon the herb butter mixture evenly over each chicken breast, ensuring full coverage on all sides.
06 - Pour chicken broth into the baking dish around the chicken, not directly over it. Top each breast with the remaining lemon slices.
07 - Cover the baking dish tightly with aluminum foil and bake for 25 minutes to steam the chicken with the aromatics.
08 - Remove the foil and continue baking for an additional 15 minutes, or until the chicken reaches an internal temperature of 165°F and develops a light golden color.
09 - Remove from the oven and let the chicken rest for 5 minutes before serving. Sprinkle with fresh chopped parsley just before plating.