Soak the dried beans in cold water for four hours or overnight and drain.
Roughly chop the onion, celery, and carrots then peel and chop the garlic.
Heat oil in a large pan and add onions, carrots, celery, garlic, bouquet garni, and lardons.
Cover the pan and sweat the vegetables over a low heat for 15 minutes.
Add beans and enough water to cover them by 8cm.
Boil hard for 10 minutes then simmer gently covered until beans are tender.
Add tomatoes, cumin, oregano, seasonings, sherry, and lime juice once beans are soft.
Simmer for 30 minutes while occasionally crushing some beans against the pan side.
Remove the bouquet garni and adjust seasoning with salt and pepper.
Serve the hot soup with bowls of avocado, cream, spring onions, chillies, and coriander.