In a large pot, pour in the chicken broth and add fresh lemon juice, shredded carrots, finely chopped onion, and celery. Incorporate your chicken soup base and ground white pepper, then bring the mixture to a vigorous boil over medium-high heat. Once boiling, reduce the heat to low and simmer for 15-20 minutes, or until the vegetables are tender and aromatic.

While waiting for the vegetables to soften, create a thickening paste by combining margarine and all-purpose flour in a small bowl until smooth. Gradually stir this paste into the simmering soup, ensuring it’s well incorporated. Continue cooking for an additional 8-10 minutes, stirring occasionally until the Greek Lemon Chicken Soup thickens slightly and begins to have a rich, creamy texture.

In a separate bowl, beat the egg yolks until pale and frothy. To avoid curdling, gradually add a ladleful of the hot soup to the egg yolks, mixing gently. Slowly pour this mixture back into the soup pot while stirring continuously, warming through without letting it reach a boil.

Stir the cooked white rice and diced cooked chicken into the soup mixture, ensuring everything is evenly heated. Keep on low heat, allowing the soup to warm thoroughly, which should take about 5 minutes.

Once the soup is heated through, ladle the Greek Lemon Chicken Soup into warm bowls. For a finishing touch, garnish each bowl with fresh lemon slices and, if desired, a sprinkle of fresh herbs like dill.