Season the Chicken: Preheat your oven to 375°F. Pat the whole chicken dry with paper towels, then season it generously all over with salt, black pepper, thyme, oregano, paprika, and garlic powder. Don't forget to season inside the cavity as well for even more flavor. Place the lemon halves inside the cavity to infuse the chicken with a subtle citrus aroma as it roasts.
Sauté the Vegetables: Heat the olive oil and butter in a large Dutch oven over medium heat. Add the onion, carrots, and celery, then cook until the vegetables begin to soften and the onion turns translucent. Stir in the minced garlic and cook for another 30 seconds, just until fragrant.
Roast the Chicken: Nestle the seasoned chicken on top of the vegetables, then carefully pour the chicken broth and white wine around the chicken. Bring the liquid to a gentle simmer on the stovetop, then cover the Dutch oven with its lid and transfer it to the preheated oven. Roast for about 1 hour, allowing the chicken to slowly cook while creating a rich, flavorful broth.
Add the Orzo: Carefully remove the Dutch oven from the oven. Scatter the uncooked orzo around the chicken, gently stirring it into the broth without disturbing the chicken too much. Cover the pot again and return it to the oven. Continue cooking until the orzo is tender and the chicken reaches an internal temperature of 165°F.
Finish the Soup: Transfer the chicken to a cutting board and let it rest for about 10 minutes before carving or shredding the meat. Meanwhile, stir the orzo and vegetables together. If you're using spinach, stir it into the hot soup and let it absorb naturally. Taste the broth and adjust the seasoning with additional salt and pepper if needed.
Serve and Enjoy: Return the shredded or carved chicken to the Dutch oven, or spoon the orzo into bowls and top each serving with chicken. Finish with a generous sprinkle of chopped fresh parsley and serve warm with crusty bread or dinner rolls for a cozy homemade meal.