Begin by heating the olive oil in a large pot over medium heat. Add the diced onion and sauté for approximately 2-3 minutes, or until the onion becomes translucent and fragrant.
Incorporate the minced garlic along with the diced carrots and celery into the pot. Continue to cook, stirring occasionally, for about 5 minutes until the vegetables begin to soften.
Add the boneless, skinless chicken breasts to the pot and pour in the low-sodium chicken broth. Bring the mixture to a boil, then reduce the heat to a gentle simmer. Let it cook for 15-20 minutes or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
Once cooked, carefully remove the chicken breasts from the pot. Using two forks, shred the chicken into bite-sized pieces and return it to the pot, stirring to combine.
Add the orzo pasta to the pot and allow it to simmer for an additional 8-10 minutes, or until the orzo is al dente and perfectly tender.
Reduce the heat to low. Gently stir in the chopped spinach, half-and-half (or whole milk), lemon zest, and freshly squeezed lemon juice. Allow the soup to warm together for an additional 2-3 minutes, ensuring the spinach wilts and the flavors meld beautifully.
Season the soup with salt and pepper to taste, adjusting according to your preference for flavor.
Serve the soup hot in bowls, garnished with a sprinkle of freshly chopped parsley for a burst of color and added freshness.
Notes
For a lighter version, use whole milk instead of half-and-half.