- 30g/1oz unsalted butter
- 70g/2½oz onions, sliced
- 250ml/9fl oz chicken stock
- 400g/14oz Jerusalem artichokes, peeled and cut into small pieces
- 1 bouquet garni
- 50g/1¾oz butter
- few drops truffle oil
- 1 tbsp chopped fresh chives
- salt and freshly ground black pepper
- Melt the butter in a saucepan, add the onions and a pinch of salt and cook gently until soft, without colouring. Add 250ml/9fl oz water, the chicken stock, artichokes and bouquet garni and bring to the boil. Cook for about 30 minutes. Once the artichokes are soft, remove the bouquet garni. Transfer to a blender and blend to a fine purée, then pass through a fine sieve if needed.
- Whisk the butter into the soup, add a few drops of truffle oil, then season with salt and pepper.
- Serve with a sprinkling of fresh chives.