Saute the chopped onion, celery and carrots in the butter and oil, until the onions are translucent.
Add the flour, with salt and pepper and cook the flour for about a minute.
Add the chicken stock and fresh lemon juice and stir to loosen the flour and all the bits of caramelized onion from the bottom.
Add rice, bring to boil, stirring frequent enough to keep the rice from sticking, and then turn the heat down to low.
Cover and let simmer for about 20 minutes, or until the rice is tender.
Add the chicken, spinach, honey, salt, and pepper.
Beat the egg yolks until light in color. Gradually add some of the hot soup to the egg yolks, stirring constantly.
Return the egg mixture to the soup pot and heat through.
DO NOT boil the soup once you add the egg yolks.