Heat oil and butter in a large pot over medium heat. Once melted, add onions, carrots, and celery then sauté for several minutes, until softened. Add garlic and cook for 30 seconds.

Add chicken, Italian seasoning, thyme, rosemary, and chicken broth. Bring to a boil, reduce heat, and simmer for 10 minutes (or until chicken reaches 160 degrees F).

Remove chicken to a plate, cover with aluminum foil, and allow to rest before chopping in pieces.

Stir in orzo and cook for 8 more minutes, stirring occasionally, until tender.

Reduce heat to low and stir in lemon juice, zest, cream, parsley, and season generously with salt and pepper. Return the chicken to the pot. Taste the soup and add additional seasonings or bouillon if needed.