Step 1: Sauté the Aromatics
In a large stockpot or Dutch oven, heat the olive oil over medium heat. Add the diced onion, celery, and carrots (this is a sofrito or mirepoix). Cook, stirring occasionally, for 7-8 minutes until the vegetables have softened but not browned. Add the minced garlic and cook for one more minute until fragrant.

Step 2: Build the Broth
Pour the chicken broth into the pot. Add the bay leaf, thyme, and a good pinch of salt and pepper. Bring the broth to a boil, then reduce the heat to a gentle simmer.

Step 3: Cook the Chicken
Add the raw chicken thighs or breasts to the simmering broth. Ensure they are fully submerged. Let them poach gently for 15-20 minutes (for thighs) or 12-15 minutes (for breasts), or until cooked through and tender.

Step 4: Cook the Rice
Remove the cooked chicken from the pot and set it aside on a cutting board to cool slightly. Add the uncooked rice to the simmering broth. Cook for 15-18 minutes, or until the rice is tender.

Step 5: Shred the Chicken
While the rice is cooking, use two forks to shred the cooled chicken into bite-sized pieces.

Step 6: Prepare the Avgolemono Sauce
This is the most crucial step. In a medium bowl, whisk the 3 eggs until frothy. Gradually whisk in the fresh lemon juice until the mixture is smooth and homogenous.

Step 7: Temper the Eggs (Do Not Skip!)
To prevent the eggs from scrambling when they hit the hot soup, you must temper them. Using a ladle, slowly scoop about 1 to 1.5 cups of the hot broth from the pot. While whisking the egg-lemon mixture constantly, very slowly drizzle the hot broth into the bowl. This gradually raises the temperature of the eggs. Continue until all the hot broth is incorporated.

Step 8: Finish the Soup
Remove the soup pot from the heat. Discard the bay leaf and thyme sprigs. Slowly pour the tempered avgolemono mixture back into the pot, stirring constantly. The residual heat will thicken the soup to a beautiful, silky consistency.

Step 9: Final Additions
Stir the shredded chicken and the chopped fresh dill or parsley into the soup. Taste and adjust seasoning with more salt, pepper, or lemon juice as needed.

Step 10: Serve and Enjoy
Ladle the soup into bowls and serve immediately. The soup will thicken as it stands, so it is best enjoyed fresh.