200g/7oz cooked broad beans
1 large onion, finely chopped
150驳/5陆辞锄 runner beans
1 heaped tbsp chopped fresh herbs (a mixture of chervil, tarragon, chives and flatleaf parsley)
300驳/10陆辞锄 risotto rice
salt and freshly ground black pepper
dash olive oil
1 litre/1戮 pints vegetable stock
3 knobs butter
3 tbsp mascarpone (optional)
50g/2oz parmesan (or similar vegetarian hard cheese), finely grated, plus extra to serve