Perfect riboletta (warming Tuscan winter soup)

Felicity Cloake's recipe for this traditional, thrifty, Tuscan soup is a delectable mishmash of vegetables, beans, cheese and stale bread, making it perfect for using up all sorts of odds and ends.  

Ingredients:

• 1 x 400g tin cannellini beans 
• 2 tbsp olive oil
• 1 smallish onion, peeled and finely chopped
• 1 smallish red onion, peeled and finely chopped
• 2 carrots, trimmed and finely chopped
• 2 sticks celery, trimmed and finely chopped
• 2 garlic cloves, finely chopped
• Salt and black pepper
• ¼ tsp fennel seeds (optional)
• ¼ tsp chilli flakes (optional)
• 1 large leek, washed and thickly sliced
• 200g winter squash, peeled and cut into rough 1cm chunks
• 250g cavolo nero, shredded
• 1 x 400g tin chopped tomatoes
• 1 parmesan rind (or similar hard cheese rind; optional)
• 200g stale bread, torn into chunks
• Extra-virgin olive oil, to serve
• Grated cheese, to serve
• 2 spring onions, trimmed and sliced into long strips, to serve (optional)

Method:

1. Scoop out half the tinned bins, then puree the rest with the liquid from the can.
2. Put the oil in a large pan on a medium heat, then saute the onions, stirring, for six or seven minutes, until they soften. Add the carrot, celery and a pinch of salt, and cook for five or so minutes more, until soft. Finely chop the garlic and stir it into the pan.
3. Stir in the fennel seeds and chilli flakes, if using, cook for a minute, then add the leek, squash and cavolo nero, stir well, then cover and cook, stirring occasionally, until limp.
4. Tip in the tomatoes, pureed beans and cheese rind, adding 150-250ml water (or stock), if necessary, depending on how liquid the puree is and how soupy you want your ribollita to be.
5. Cover again and leave to bubble for about 40 mins, or until the vegetables are cooked to your taste.
6. Stir in the remaining beans and the bread, cook until the latter is soft, then season the soup to taste. Drizzle with extra-virgin olive oil and pop under a hot grill until crisp on top, or serve just as it is. Top with grated cheese and spring onion, if using.