For the gumbo, heat the fat in a large pan, add the flour and cook over a gentle heat, stirring continuously, until it has turned a golden biscuit brown. Add the bacon and continue to cook for 2 minutes. Gradually add the stock, stirring as you do. Now add the onion, celery and green pepper, plus the okra, tomatoes, jalapeno chilli, thyme and bay leaves. Leave everything to simmer for 25 minutes. The vegetables need to be very well cooked, almost blending into the now beautifully flavoured sauce. Add the chicken after 20 minutes and add the prawns, clams or mussels shortly after. Finally, stir in the crab meat, spring onions, parley, 1½ tsp of salt and some freshly ground black pepper.