Spring leek soup

1l vegetable or chicken stock, heated

3 medium sized leeks, white only, sliced into medium thick rounds

1 medium carrot, peeled and finely chopped

1 celery stalk, thinly sliced

4 spring onions, thinly sliced

handful of washed and roughly shredded spinach or chard leaves

1 tbsp olive oil or 30g butter

zest of ½ lemon

sea salt

black pepper

1 tbsp of light miso paste (optional)