Georgian chicken soup thickened with egg yolks (Chikhirtma)

1. Put the chicken in a large pot, cover with 2.5 litres of cold water, bring to the boil, skim off the foam and simmer gently for 1 hour; lift out, strain the broth, strip the meat from the bones and tear into bite-sized pieces.

2. Very finely chop the onions and cook slowly in the butter, stirring, for 8-10 minutes until soft and golden; sprinkle with the flour and cook together for 1 minute.

3. Gradually pour the hot chicken broth over the floured onions, stirring constantly, add the chicken, season with salt and pepper and simmer gently for 10 minutes.

4. In a bowl, whisk the egg yolks with the wine vinegar; slowly, in a thin stream and whisking hard, add 2 ladles of hot soup so the yolks don't curdle (tempering).

5. Take the soup off the heat and pour the tempered egg mixture back in, stirring constantly; this makes it silky and creamy – don't let it boil again, just warm it over low heat for 1-2 minutes at most.

6. Stir in the chopped coriander and serve straight away; Georgians say chikhirtma is the best remedy the morning after a long festive feast.

Tip: Tempering is the key: if you pour the eggs into the hot soup too quickly, you'll get scrambled eggs. Instead of wine vinegar you can sharpen it with lemon juice.