1 large carrot, cut into small chunks
1 celery stalk, cut into small chunks
150g/5oz green beans, trimmed
1 leek, cut into small chunks
1 sweet potato, cut into small chunks
small bunch thyme, tied together with string (optional)
1 x 400g/14oz can chopped tomatoes
2 tbsp balsamic vinegar
sea salt and freshly ground black pepper
1 tsp ground cumin
1 tbsp olive oil
570ml/1 pint vegetable stock
1 raw chorizo sausage (about 110g/4oz), cut into small chunks