Build the chicken broth

• Place the chicken thighs in a stockpot with the onion, carrot, celery and bay leaf.
• Cover with the water, season with salt and bring to a gentle simmer.
• Skim the foam, then simmer until the chicken is cooked through and tender.

Strain and shred the chicken

• Remove the chicken and set aside to cool slightly.
• Strain the broth through a colander, discarding the vegetables, and return the broth to the pot.
• Shred the chicken, discarding the bones, and keep warm.

Cook the rice in the broth

• Bring the broth back to a simmer and stir in the rice.
• Cook until the rice is tender and the broth has reduced slightly.

Make the avgolemono

• Whisk the egg whites in a bowl until frothy, then whisk in the yolks and the lemon juice.
• Slowly ladle hot broth into the egg mixture while whisking constantly to temper it.

Finish the soup

• Off the heat, pour the egg-lemon mixture into the pot, whisking continuously.
• Return the shredded chicken, stir in the olive oil and season with salt and pepper.
• Warm gently without boiling until thickened and creamy, then serve.