Chicken, lemon and orzo soup

Method

1. Put the chicken and onion in a large saucepan and cover with 1.5 litres cold water. Cover and bring to a simmer, then leave to cook gently for about 15 minutes, until the chicken is cooked through. Lift the chicken out onto a board and scoop out a large mugful of the broth.
2. Bring the liquid left in the pan back to the boil, add the orzo and cook for 2 minutes less than it says on the packet. Meanwhile, shred the chicken with two forks. When the orzo is done, return the chicken to the broth and keep over a low heat.
3. Put the eggs in a bowl and juice 1½ of the lemons, cutting the final half into wedges to serve. Use a balloon whisk to whip the eggs for a few minutes until frothy, then continue whisking while adding the lemon juice. Slowly add the mugful of reserved liquid, still whisking. Once all combined, pour the mixture into the pan of orzo and chicken and add the spinach. Cook, stirring, for about 3 minutes, to thicken the soup a little, but be careful not to boil it.
4. Season the soup with salt then divide between bowls and serve with plenty of black pepper on top and the lemon wedges on the side.