• Melt butter in a large saucepan over a low heat.
• Add finely sliced leek and celery. Cook gently until very soft, about 10 minutes.
• Stir in garlic and then pour in chicken broth.
• Add peas and sliced lettuce. Simmer gently for 10 minutes, adding a little more broth or water if necessary.
• Stir in mint leaves then puree soup until smooth with a stick blender.
• Add salt and pepper, taste for seasoning and serve topped with a dollop of creme fraiche or yoghurt.

Optional Ideas:

• Try this soup with kale, spinach, zucchini or broccoli in place of the lettuce.
• Top the soup with ricotta, fetta or goats cheese instead of the creme fraiche.
• Add a squeeze of lemon juice to each bowl of soup.
• Add 3 sliced rashers of bacon when cooking the leek.