This delicious vegetable soup features the national emblem of Wales,, the leek, and is also known as Cawl Cennin, the word 'cawl' meaning broth. Because the leek season is short (January to March) it's a good idea to freeze some since all the other ingredients for the soup are available all year round.

SERVES 6 - 8 (AS A STARTER)

25 g (1 oz) butter

700 g (1 1/2 lb) leeks, trimmed, sliced and washed

2 medium onions, skinned and roughly chopped

2 celery sticks, chopped

1.1 litres (2 pints) chicken stock

salt and pepper

150 g (5 oz) natural yogurt

snipped fresh chives, to garnish

1. Melt the butter in a large saucepan, add the leeks, onions and celery and cook gently for 10 minutes, until softened but not browned.

2. Add the stock. Season to taste and bring to the boil, then cover and simmer for 30 minutes, until the vegetables are tender.

3. Allow to cool slightly, then puree in a blender or food processor until smooth.

4. Return to the saucepan, stir in the yogurt. Adjust the seasoning and reheat gently without boiling.

Serve hot, garnished with snipped chives.