Preheat the oven to 375°F and lightly grease a 9×13 baking dish.
Season the chicken on both sides with salt, pepper, paprika, and oregano, then set aside.
Add the dry orzo to the prepared baking dish. Pour in the chicken broth and olive oil, then stir in the garlic and lemon zest until evenly combined.
Nestle the seasoned chicken into the orzo mixture. Cover the dish tightly with foil and bake for 30 minutes.
Remove the foil and gently stir the orzo around the chicken. Return the dish to the oven and bake uncovered for 12–15 minutes, or until the orzo is tender and most of the liquid has been absorbed.
Carefully transfer the chicken to a plate and loosely cover to rest.
Add the Boursin cheese, spinach, and lemon juice to the hot orzo and stir until the cheese melts into a creamy sauce and the spinach wilts.
Return the chicken to the baking dish and let everything rest for 5 minutes before serving.
Slice or leave the chicken whole, then garnish with parsley, cracked black pepper, and lemon zest.
