Watercress and Pear Soup

Normal soup with those two things thrown in. It was meant to be watercress and pea but the last minute addition of pear was stronger. Watercress is great gear when you can buy it, yesterday was the first time I had seen it in 6 years and it was cheap too. It is quite peppery and is great in salads and as a garnish. If you like the sound of this but can't find watercress, use rocket perhaps or, maybe even try adding some blue cheese. Blue cheese and pear together are awesome.

1 bunch watercress washed and cleaned
2 leeks cleaned and chopped
1 onion chopped
2 sticks of celery chopped
2 cloves garlic chopped
4 or 5 small potatoes chopped
750 ml chicken stock
2 cups frozen peas
1 1/2 pears chopped
Lemon
2 tbs yoghurt  (or more)
Salt and pepper
1 tbs butter
Extra virgin olive oil

Saute the onion, celery, leeks and garlic in the butter in a large saucepan. Add the potato and cover with the stock. Simmer for about 20 minutes or until just tender. After10 minutes add the pear. After 15 minutes add the peas. After 20 minutes, add the watercress, mix in and turn off the heat for a couple more minutes. Add salt and pepper, yoghurt and some lemon juice (start with about 1 tbs) and blend with a stick blender. Check for seasoning adding more salt, pepper, lemon or yoghurt as necessary.
Serve in bowls, drizzle with some extra virgin olive oil, with some crusty bread.