Heat olive oil and butter in a large stock pot over medium heat.
Cook and celery and onion until the vegetables begin to soften and the onion becomes translucent, 5-7 minutes.
Season the mixture with Adobo, salt and pepper. Continue cooking another 30 seconds before pouring the broth into the pot.
Bring the broth to a boil. Partially cover the pot, reduce heat to medium low and simmer until the vegetables are tender. About 10 minutes (I prefer the carrots firm so I steam them separately and put them in the soup at the last minute before serving).
Squeeze the lemons into the broth as well as the shredded cooked chicken and cook until heated through about 5 minutes.
Separately boil the orzo in salted water and drain. When the orzo is boiled, combine into the soup.
Add the spinach and parsley until the spinach wilts into the broth, 2-3 minutes. Throw the carrots into the soup.
Ladle soup into the bowls, garnish with lemon slices and grated cheese.