Using the Instant Pot, or in a large pan - sauce the onion, celery and garlic for 2-3 minutes until softened.
Add the lamb and fry for a further 5 minutes before adding the beans, bay leaves, chicken stock and 1 litre of water.
Cook on high pressure for 60-70 minutes using the Instant Pot
Simmer gently for 2-3 hours over a low heat for traditional pan.
Continue until the beans are soft and creamy - this time can vary.
Once done, remove half the beans and using a stick blender or food processor blend them into a thick puree. Return this to the pan and stir through to create a creamier texture to the soup.
Serve with lots of crusty bread.