A favourite soup from Nigel Slater.
Heat the olive oil in a large pan over a medium heat, and fry the onions for 5 minutes, or until soft and pale golden in colour. Add the turmeric and garlic and cook for a further 4 minutes.
Add the chickpeas, lentils and haricot beans to the onions and pour in the stock. Simmer for 30 minutes, stirring occasionally.
Melt the butter in a non-stick frying pan over a low heat. Fry the sliced onions for 20 minutes, stirring occasionally, until they are deeply caramelised.
When the beans have simmered for 30 minutes, add the noodles to the pot and cook for a further 10 minutes.
Wilt the spinach in a pan with a little water for 2 minutes, drain and squeeze as much liquid out as you can. Roughly chop the spinach on a board, along with the parsley, coriander and mint.
Stir the spinach and herbs into the noodles and beans. Fold in the soured cream and serve with the caramelised onions on top.