Drain and rinse the soaked beans.
Put the olive oil, spring onion whites, celery, carrot, half the red chilli, and all the rosemary in a heavy-based pan and cook on a medium-low heat, stirring, until the vegetables start to soften and turn translucent.
Add the soaked beans, one and a half litres of fresh water and a pinch of salt, bring to a boil, then turn down the heat and simmer for an hour, or until the beans are soft.
Remove half the soup, blend it smooth, then return to the pan with the coconut cream and salt to taste.
Put the pan back on the heat and bring to a lively simmer.
Add the broken tagliatelle and simmer, stirring regularly, until the pasta is cooked - you might need to add a bit more water.
Serve, topping each bowl with the sliced spring onion greens and a little extra chopped red chilli, and encouraging those who want to add a squeeze of lemon.
