In a large pot, combine 8 cups of chicken broth, the juice of 2 lemons, 1 cup of shredded carrots, 1 finely chopped onion, and 1 finely chopped celery stalk. Add 2 tablespoons of chicken soup base and 1 teaspoon of ground white pepper. Bring to a gentle boil over medium-high heat, then reduce and simmer for 15-20 minutes until vegetables are tender.

In a small bowl, blend 2 tablespoons of margarine and 2 tablespoons of all-purpose flour to form a smooth paste. Gradually stir into the soup, mixing well. Cook for an additional 8-10 minutes until slightly thickened.

In a separate bowl, beat 3 egg yolks until light. Slowly whisk in about 1 cup of hot soup to temper the yolks, then pour this mixture back into the pot, stirring continuously over low heat until warmed through.

Stir in 1 cup of cooked white rice and 2 cups of diced cooked chicken. Let the mixture cook for another 5 minutes until heated through.

Ladle the soup into bowls and garnish with a slice of lemon. Serve with crusty bread or a fresh salad.