Β½ carrot, peeled, halved lengthways
Β½ celery stick
1 garlic clove
Β½ leek, trimmed, halved lengthways
Β½ onion, peeled, halved
1 sprig thyme
650g/1lb 7oz dried white beans (such as coco or cannellini), soaked overnight
265g/9oz Old Winchester cheese, grated
8 live fresh razor clams, washed under running water to remove any grit (discard any clams that do not close tightly when tapped)