Welsh Leek Soup

From The Dairy Book of British Food. "This delicious soup features the national emblem of Wales, the leek, and is also known as Cawl Cennin, the word 'cawl' meaning broth".

• Ready In: 50 mins
• Serves: 6

Ingredients

• 1  ounce butter
• 1 1⁄2 lbs leeks, trimmed, slices and washed
• 2  medium onions, roughly chopped
• 2  celery ribs, chopped
• 2  pints  chicken stock
•  salt and pepper
• 5  ounces plain yogurt
•  snipped fresh chives, to garnish

Directions

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 (hand held) food processor until smooth.
4. Return to the saucepan, stir in the yogurt. Adjust the seasoning and reheat gently without boiling.
5. Serve hot, garnished with snipped chives.