1 large onion
2 sticks celery
10g fresh lemon thyme, plus extra to garnish
50g walnut pieces, toasted
1 tbsp olive oil, plus extra for drizzling
½ tsp fennel seeds
750ml hot vegetable stock
500ml semi-skimmed milk
Grated lemon zest and/or chopped parsley, to garnish (optional)
1 Finely chop the onion. Peel the celeriac and dice into 1cm cubes. Trim and slice the celery. Strip the leaves from the lemon thyme. Roughly chop the walnut pieces.
2 Heat the oil in a large saucepan over a high heat. Add the prepared vegetables and fennel seeds then cover and cook gently for 5 minutes. Stir in the lemon thyme and the stock and bring to the boil. Cover and cook for 20 minutes.
3 Add the milk to the soup with half of the walnuts and blend until smooth, in batches if necessary. Season to taste and reheat. Ladle into bowls and scatter over the remaining walnuts and lemon thyme leaves. Garnish with the zest, parsley and olive oil, if using.
Image and recipe courtesy of Waitrose.com