01 -
Sauté the celery, carrots, and onions in a large soup pot with the butter and olive oil over medium-high heat until the vegetables start to soften and release their aroma, about 5 to 7 minutes.
02 -
Add the minced garlic to the pot and cook until fragrant, about 30 seconds, then sprinkle in the flour, stirring continuously for about a minute to form a smooth roux.
03 -
Gradually pour in the chicken broth, stirring to dissolve the flour mixture, until smooth. Add in the Italian seasoning and the whole chicken breasts. Bring the soup to a boil.
04 -
Once boiling, reduce the heat and let the soup simmer with the lid slightly ajar for 15 minutes, allowing the chicken to cook gently and the flavors to meld together.
05 -
Stir in the uncooked orzo, and continue to cook the soup uncovered, stirring occasionally to prevent sticking, until the orzo is tender, about 10 more minutes.
06 -
Remove the chicken breasts, cut them into bite-sized pieces, and return them to the pot. Add lemon juice, parsley, and adjust the seasoning with salt and pepper to taste. Serve hot, garnished with additional fresh parsley if desired.