Ciorbă rădăuțeană

Step 1: Put the 2 ¼ lb bone-in chicken thighs in a large pot with the 10 ½ cups cold water and 2 tsp salt and bring slowly to the boil over a medium heat. Skim off the grey foam as it rises for 5 minutes, until the surface is clear.

Step 2: Add the 1 onion, 2 carrots, 1 parsley root or parsnip, 3 ½ oz celeriac and 1 tsp black peppercorns, lower the heat and simmer very gently, uncovered, for 45 minutes, until the chicken is falling from the bone and reads 165°F at the thickest part.

Step 3: Lift out the chicken and the onion. Discard the onion, strip the meat from the bones in bite-sized shreds and return it to the pot with the vegetables.

Step 4: In a large bowl whisk the 3 egg yolks with the 9 oz sour cream (20% fat) and 6 cloves garlic until smooth.

Step 5: Temper the mixture: whisk in a ladle of hot broth, then another and another, about 5 ladles in all, until the bowl feels hot to the touch.

Step 6: Turn the heat under the pot to low so the soup is no longer bubbling. Pour in the tempered mixture in a thin stream, stirring all the time.

Step 7: Heat gently for 4–5 minutes, stirring, until the soup is steaming, slightly thickened and silky, around 176°F. Keep it below a boil from now on or it will curdle.

Step 8: Stir in the 3 tbsp white wine vinegar a spoon at a time, tasting as you go, until pleasantly sour. Serve straight away, scattered with ⅓ oz flat-leaf parsley, with a 6 fresh hot pepper on the side. Reheat leftovers gently, without boiling.